I'll start with the writing style.
Well, I know that each writer has its own style, and I understand when you want to make a point using pauses. My problem is that in almost each paragraph there was a set of suspension points ("..." or ellipsis), or two or more. This is a very common issue, don't worry. But it does not change the fact that they were very distracting from what I guess you were trying to say. Try to use more a simple comma or period, they make the page look less dirty, and they represent the pause you are looking for, because the use of the ellipse indicates a veeery long pause. More than 30 secs, that's for sure. Also I noticed some grammar mistakes.
Now, let's talk about the story. I really didn't feel chemistry between the two main characters. They were very cold with each other for a very long while and their interactions left me expecting so much more. Also, I felt that the plot was kind of stupid at the end: they had very serious problems as a couple, he noticed she was cold and sad, but didn't wanted to tell her what was happening to him because he didn't wanted to "upset" her. He wanted her to trust him, to not make questions about the huge problem he has. But not telling her caused that she thought He didn't trusted her, and then with her insecurity and jealousy, she started to imagine a lot of things that weren't actually happening. But I I Ind of get her: she is not only aware that he is keeping a secret, she also know he is lying to her, is going somewhere with someone, and she can't really do much, because her pregnancy is of high risk and is trapped in her house, in her bed for weeks and that is very, very frustrating. All that together and is no wonder all her turmoil is concentrated in the person closer to her, who also is the very person at fault for a lot she is going through.
But at the end, it was just the telling of how a marriage can easily fall apart if you aren't one hundred percent honest and if you don't fix things in the moment.
I thing that even if she wasn't a main character, the lights in this book were all on Shannon. And poor Lily was in second place, because let's admit it: since the moment of her first visit and her later ultimatum, she was the very thing that was in my mind while they were fighting; and Drake planned his schedule and a great part of his thoughts, even tough negative, were revolving and focused around her.