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If I'm as straight as I always thought, why does kissing my best friend feel so right?

Zach has been my ride or die since we were nine. Business partners, roommates, best friends...we do everything together. But the last thing either of us expected was to be staring forty in the face just as single as we both were when we made a silly, drunken marriage pact twenty years ago. The problem? Zach is gay…and, well, I’m not.

Under pressure from family, that pact comes rushing back, and I lock us into a fake engagement. But is it possible some part of me wants it to be real?

Convincing Zach I’m legit is another story. With each passing day, I wonder if my feelings of affection for my best friend can morph into the love I desperately want in my life. Something in Zach’s eyes tells me we can have it all if we just try.

It may have taken me a lifetime to see Zach with new eyes, but with every touch and discovery, it’s been worth the wait. On the edge of Dirty Forty, it’s time to go for it.

All I have to do is convince Zach it’s real.


Dirty Forty is a best friends to lovers, marriage pact, demi/bisexual awakening featuring thirty years of pining, a fake engagement, curious kisses, and two guys finally embracing what’s always been in front of them.

240 pages, Kindle Edition

First published February 25, 2021

434 people are currently reading
997 people want to read

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Mia Monroe

64 books723 followers

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5 stars
818 (31%)
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855 (33%)
3 stars
621 (24%)
2 stars
213 (8%)
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52 (2%)
Displaying 1 - 30 of 358 reviews
Profile Image for ~✡~Dαni(ela) ♥ ♂♂ love & semi-colons~✡~.
3,579 reviews1,118 followers
March 27, 2021
This was my first Mia Monroe book, and I can't say I'm impressed. Dirty Forty was bland and predictable. I wanted to DNF, but I persevered.

Sadly, the second half was even more boring than the first. Once Dominic realized he was into Zach, the romance became unbearably sappy.

All the characters were interchangeable, and the voices of the MCs were so similar, I would get confused as to who was narrating and talking. Plus, the men sounded much, MUCH younger than 40. They talked like stilted, overly polite teenagers.

And the dialogue .... dear god, the dialogue was terrible - clunky, simplistic, wooden. This is not how people talk.

To sum up: no angst, no tension, no plot but plentiful sex, which I admit was hot. It wasn't enough to save the book though.
Profile Image for D.L. Howe.
Author 25 books600 followers
September 5, 2023
Re-read 9/1-9/3/23
⭐️⭐️⭐️⭐️
🌶️🌶️

RTC

Original Review 11/25-11/26/21

Dirty Forty is the equally adorable as it is steamy story about best friends. This is what happens when your straight best friend realizes that’s there’s more then meets the eye in their lifelong friendship.

Both Dom and Zach have been unlucky in love. On Dom’s 39th birthday he recalled a promise he made with Zach on his 21st. That if they both reached 40 single that they would marry each other.

The problem is Zach has always been in love with Dom but Dom is straight as an arrow. But then Dom folds under the pressure of his marriage meddling Italian mama and tells her and his whole family that he’s engaged to Zach.

Slowly but surely in the oncoming months Dom realizes that he is attracted to his best friend. They’ve always been platonic soulmates, they own a business, they work together everyday, & they live together. And when they’re not forcing themselves to go on mediocre dates, they spend all their time together.

Witnessing Dom fall in love with Zach is everything I adore about romance. It’s perfect in every way, especially when Zach feels like it’s too good to be true and he’s riddled with doubts. Dom knows him so well, he knows exactly how to put his mind at ease and he never gets irritated either. The love they share just flourishes and blooms so beautifully.

This was a five star read, one of my favorites of the year until about the 70% mark. At that point it all just petered out, became dull compared to the rest of the story. I wish the writer had created more conflict, it would’ve added a lot not only to the plot line but to strengthen their relationship.

Even though that last 30% left me wanting more it was still an adorably fun read. The steam was some of the best, the chemistry between these best friends was off the charts. I’ll definitely be reading more by Ms Monroe
Profile Image for Lelyana's Reviews.
3,412 reviews400 followers
February 27, 2021

To be honest, it was really good in the beginning after fifty percent mark, and went downhill after that.
I liked Dominic, but Zach insecurity was annoying. Sure I liked Zach, but he needed more self esteem than this.
The best part of this book was the prologue, I really liked it, it was a promising good best friends to lovers trope.
This story has no angst at all, in my opinion, fluffy, establish couple kind of thing, even almost twenty years of togetherness as best friend. They never argued. Always live in peace and in sync.
How boring.
I like Mia's books, but too bad this one did not really wow-ed me :(
So, 2.5 rounded up?
Profile Image for lakshmi.
706 reviews555 followers
March 15, 2021
“What are you saying, Zach?”
Please, say the words, Zach. Please. I want to say them back to you so badly. Please say them.
“I love you, Dominic.”

Oh so adorable. This is 100% fluff and a stress free read. I didn’t go into this waiting for the other shoe to drop or for them to have “the fight”.

Best friends Dominic( straight ) and Zach( gay ) fake their engagement to appease their parents and soon develop a cautious and curious relationship that’s so teeth achingly sweet. >> 3.5 stars
Profile Image for Emma.
906 reviews58 followers
March 24, 2021
Goodness was this boring. They are both very nice and earnest and dull. And it just goes on and on.
2 stars.
Profile Image for Tia.
142 reviews14 followers
March 28, 2021
This book was like one long happy epilogue bursting with hearts and flowers. Zach and Dominic have been best friends since childhood and even though Dom is straight, they made a pact to marry each other if they were still single at forty. Then one night Dom lies to his mom telling her they ARE getting married to get her off his back about not being married, Zach’s parents find out, and things snowball from there.

But while they pay lip service to their parents on to the sham wedding planning, Dom is exploring his real feelings for his best friend on a sexual level. A kiss here, a blowjob there, and Dom has fallen hard. Now he just has to convince Zach that his feelings are real.

This book had zero edge or angst, no real conflict to speak of, and these characters were almost disgustingly perfect and loving towards each other. (Couldn’t they have had had just one teensy tiny single flaw?) Even the secondary characters were all completely and utterly understanding and so darned perfect!!

But I’m a sucker for best friends to lovers stories and this one had me reading until their perfect HEA. ❤️
Profile Image for Elsbeth.
1,301 reviews40 followers
March 8, 2021
*2,5 stars*

This was such a let down for me. I expected to read a friends-to-lovers romance about 40 year olds. But it felt much more reading about 20 year olds.. Nope, a miss for me. Glad I finally finished.
Profile Image for ML.
1,602 reviews1 follower
February 20, 2021

This is really a story of great friendship that turns into so much more. Timing is everything and it’s Dom’s time to realize the love he’s been looking for this whole time can be found in Zach. This book is incredibly romantic and sweet.

The chemistry and love they share is definitely apparent to an outsider. It takes them a bit to figure it all out.

As I’m reading this book, the lyrics from AIR SUPPLY – CAN'T FIGHT THIS FEELING keep popping in my head. It’s old school but it fits this book perfectly.

The relationship development felt very real and the HEA was so perfect. I’m got to need a spin off book though. I’m going to need Sydney’s book next.
Profile Image for Alicia.
844 reviews133 followers
March 14, 2021
Man, I am hitting the jackpot with the MM books I’ve been reading lately. This one was so good. I absolutely love the GFY trope, though Dominic is described as demisexual. He’s still only attracted to one guy, his best friend Zach, so it feels pretty GFY to me.

Dominic and Zach became best friends in 3rd grade when they were 9 years old. Zach soon realized that he was in love with his best friend, but Dominic is straight. When they’re 21, Zach says he’d marry Dominic if they both didn’t find anyone by the time they were 40.

Cut to years later when they’re 39 and both haven’t settled down. They live together, own a house together, run a business together... and Dominic caves to the pressure of his big Italian family when they ask when he’s going to settle down. He tells them that he’s going to marry Zach without thinking.

So they end up faking their engagement. Except Dominic starts to feel a bit more for Zach when he starts to think about it. He kisses Zach out of the blue and it just spirals from there.

This book... man. The sex was smoking hot. I don’t know what it was specifically but the scenes just got me all 🥵🥵

I thought there might’ve been some drama toward the end of the story but I was pleasantly surprised to see there was none. Dominic was such a romantic guy and the things he was saying to Zach... shit, I kept tearing up. So freaking cute.

So yes, I absolutely loved this book. Dominic and Zach have to be my favorite childhood friends to lovers book characters to date.

POV: Dual 1st person
Profile Image for Evelyn Bella (there WILL be spoilers) .
864 reviews175 followers
December 27, 2023
10/10 concept. 10/10 execution. Except for the fact that the last half of the book could be taken away, and it would make it better, not worse. Great if you're looking for a sweet, fluffy, low angst book.
Profile Image for Jamie.
1,158 reviews95 followers
January 30, 2023
3.5⭐️ - This was a very sweet story about the bonds of friendship turning to so much more. I did have to suspend reality for a bit but once I did, I was able to enjoy how goofy and fun this book was. It also had the most amazing communication between the two MCs - seriously like an aphrodisiac it was so good.

Dominic was so aloof! He was such a kind and sweet man who just wasn't always aware. He wasn't dumb, he was just kind of in his own world at times. His demi/bi-awakening was so cute! He really just went with it. As his feelings for Zach really started to take shape, you could tell how happy he was. He was genuine and so open.

Zach had been in love with Dom since they were kids. He had been out for ages but he had never mentioned his feelings. He didn't want to ruin their friendship and Dom had always been "straight." He wanted to be Dom's forever so badly but he didn't want to go into anything feeling like Dom wasn't fully aware or didn't feel obligated. Boy did he love Dom with all of his heart.

Fake engagements aren't my jam. I pretty much hate them since there is so much deception involved. And while I won't say this one has converted me, I will say that I was able to tolerate it because Dom and Zach were such sweethearts. I also couldn't get over how they communicated about EVERYTHING! It was so refreshing to read older characters who communicated like fully functioning humans. (and the irony of this statement alongside the lying about the engagement is not lost on me.)

Ooh and the sex in this book was killer. These men just knew how to please each other. Nothing was off limits and the fact that they wanted each other just as they were made it even sexier. All the yes on this one! And that Dom was like HELL YEAH anytime they did anything was fabulous.

This was fun, silly and over the top with declarations of love constantly!
Profile Image for Anna.
563 reviews
March 4, 2021
Dwóch przyjaciół. Jak się nie ochajtamy do 40 ,no to z braku laku i możemy to zrobić razem. Dwie rodziny, w tym jedna włoska, o je te włoskie mamy. I co nam wychodzi, miła , napełniona uczuciami i seksowna książka. Świetna na te szare , nudne wieczory. Polecam!!
Profile Image for Evelyn220.
651 reviews39 followers
January 26, 2023
4.5⭐️ Syrupy sweet, well-written, low-angst best friends to lovers. The plot was a little silly so I was surprised at how much I loved this. Something about it just worked. I loved that the 40 year old MCs actually acted mature and communicated well with one another. They were open and honest and respectful about their issues. It was so refreshing.
The spice and the dirty talk were super hot. Lots of praise. 🔥

The last 1/4 of the book felt like one long sweet epilogue so if you love happy endings, this one piles it on thick.
Profile Image for Stephanie Carvalho.
335 reviews
March 4, 2021
Ok, I love Mia Monroe's work, she has a way with words that capture my attention right from the first few lines. But this story here... It's hands down her best work. I can't put in words how good and sexy and swoony and adorable and very very good Dirty Forty is.

Dom and Zach are one of those characters that you cheer for instantly: they have chemistry, they get along perfectly and they are very good for each other. Here we have all kinds of feels: Zach has been in love with Dom - his straight best friend - for almost thirty years. Deep down he knows it will never happen, so he focuses on being a good friend and gets on with his life. Until things change - at first as a joke, and later with feelings involved - and from there we follow the couple as Dom starts to realise something more is there, and discovers there more than just friends when he thinks about Zach. What I really, really lived here is that Mia took her time exploring the story: we get to see how they are where they are today, what changed, what happened. It wasn't a simple "hey, I love my best friend and let's go get down and dirty"; it took time, work and a lot of effort - on both parts - to find a common ground.

The steam level is just like the author's other books: hot, intense and very well written. After I finished, I got back to reread some of my favorites... so yeah, that good.

Highly recommended book. This deserve all the stars and much much more. 
Profile Image for Jane (whatjanereads).
791 reviews238 followers
Read
April 14, 2021
This was a rather mediocre read for me personally.
It was super rushed, the conversations were very repetitive, I didn’t get the whole fake marriage thing because it actually didn’t happen because if the pact, the characters were very bland and exchangeable for me.
There is no real interaction between the two MCs that made it believable for me that they suddenly fall in love.
Then there were huge time jumps in between and all that was happening was a lot of sex.
Most of all I really HATED the parents, these guys are neatly 40 and they were so encroaching (I hope this is the right word)!!!

If you’re looking for a steamy in between read, go for it, but definitely not for a gripping plot or well thought through characters.
Profile Image for Michael S..
161 reviews106 followers
March 8, 2021
I love the tropes involved, but this didn’t fully click with me despite some great moments.

The romantic conflict lacked solid underpinnings - I wasn’t believing the false dichotomy (“Well shit, we’re almost 40 and will turn into pumpkins if we don’t get married, so these are our only choices!”). The meat of the story took only about 3/4 of the book, leaving a fairly long denouement.

On the bright side, these boys were adorable, the writing was solid, and the steam was excellent. I would read this author again.
Profile Image for Esteban Montesinos.
129 reviews1 follower
March 16, 2021
2.5 🌟

I don't know what i was expecting but this it ain't it.

I really enjoy the beginning of this book but after a moment it was just plain boring.

i think the characters were really likeable the main idea for the book was good also but that's it.
Profile Image for BWT.
2,250 reviews244 followers
April 18, 2021
This is the book equivalent of a cinnamon roll.

Warm, gooey, and covered in sweetness. Dual POV friends to lovers with a dash of fake relationship that quickly becomes real, some hot sexy times, and a lovely HEA ending.
Profile Image for Heather.
874 reviews6 followers
February 23, 2021
I loved Zach and Dominic! Honestly I’m the human heart eye emoji after finishing their story. It was the right amount of sweet, some amazing sexy (and first) times, and I had such a huge smile on my face as I was reading it! I have been so into the fake boyfriend premise recently and I was sucked right into their story. I loved that Zach and Dominic were childhood friends who had such an amazing friendship that they built a business together and shared a home. That friendship was so solid that Zach said yes to his straight best friend, Dominic, when he was asked to marry him when they were 21 if they weren’t married by 40. Flash forward eighteen years later to the unrelenting Italian mother who wanted her boy to settle down and get married. Seeing both these men navigate their fake engagement and come to feel some new emotions was amazing. With Dominic starting to realize he may not be so straight after all was wonderful. I loved how accepting he became of himself, and what he was feeling for Zach. I was so excited for Zach and couldn’t wait for him to catch up! I loved the characters we met along the way to their HEA. Speaking of HEA, one of the things I love about this author’s writing is the story doesn’t just end when the I love you’s are exchanged. You get their full relationship, you’re not left wondering what happens after the I love you. And I love that! This was a wonderful sexual awakening, friends to lovers, low angst, sweet and romantic story that left me with such warm and fuzzy feelings!
Profile Image for jut.
594 reviews221 followers
March 21, 2021
“perfect.”
“we are.”

the first half is literally perfect and lots of authors should take notes on how to deal with discovering the character's sexuality plus exploring it but the second half wasn't bad, just too many repetitive and it felt like going in circles when new things could been put down there!

but i really enjoyed dominic and zach's relationship, since the beginning, they show perfectly how a friendship should turn in a romantic/sexual relationship!
Profile Image for Ed Davis.
2,890 reviews99 followers
January 13, 2023
This was an ok book, but not my favorite by Mia Monroe. I liked Dominic a lot, but got frustrated with Zach’s insecurity. The second half of the book was too much sex and constantly saying how lucky they are and how much they love each other. It certainly had some very fine moments. Dominic’s proposal with the rings was beautiful. It’s a light fluffy read. It has no angst except for Zach’s insecurity. If you’re looking for something light you should enjoy it.
Profile Image for peach.
563 reviews40 followers
December 28, 2022
I enjoyed the development of the friends to lovers relationship and Dominic figuring out his sexuality, but there was no tension or relationship/character growth in the last third of the book which made it a bit of a slog to finish. Everything was already resolved by then, so it just felt like I was reading a multichapter epilogue for the remainder of the book.
Profile Image for Cyndy.
457 reviews10 followers
Read
August 20, 2025
DNF at 38%. I just realized I can’t go on another 60% being annoyed by the communication issues and the internal dialogue. Without that, there’s not much of a story and life is too dang short.
Profile Image for Tammy Cody.
271 reviews19 followers
March 4, 2021
Loved this sweet, low angst romance. Friends to lovers has always been a favorite of mine and add in bisexual awakening and you have my kryptonite! Definitely one that kept my attention & I didn’t want to put down!
Profile Image for Bibliophile.
855 reviews
March 22, 2021
Sweet book. I would have preferred more character and plot development, but I appreciated the sweetness in this story and the friends-to-lover storyline.
Profile Image for Shelly.
279 reviews9 followers
March 5, 2021
Best friends-to-lovers is my favorite trope and Dirty Forty is a perfect representation of this. The love, shared history, and trust between these best friends lends itself to a much stronger romantic relationship, which means the intimacy between Dom and Zach is immediately deeper and more meaningful.

Thirty years of friendship, co-habitation, and partnership primed them for one hell of a romantic relationship, once Dominic got on the same page. Their mix of flirty banter, loyalty, and solid friendship gave me all the warm fuzzies. Zach's pining was just enough to make the evolution of their love story super rewarding, without being angsty. And when they finally let themselves cross that last barrier of friendship to more? Whew! Insane levels of hotness, mixed with vulnerability and tenderness. Welcome to Swoon City, my friends!

Mia has a knack for writing mature characters who communicate well. It's so refreshing to read a book and not want to throttle the characters because they refuse to share their feelings. Super sweet and sexy as hell, with grown-up characters. Two thumbs up!
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