As Naksed says quite often, Great Big Terrible Misunderstandings can be quite irritating. I will roll my eyes occasionally, but there are far worse tropes and stupid plot points that are much worse. Until now.
This heroine has to be the dumbest, the most emotional, least rational heroine I have read in a long time or ever. Given the genre and sub-genre we're reading, that's saying something. Look at the faces of her little cherubs on the cover. Even they know something's up.
Nitwit finally wakes and remembers her life from her looonnnnngggg amnesiac state. She freaks when she sees her husband, the best, most patient, long suffering hero in RomanceLand. Turns out he's her brother. The deathbed confession from his father who, along with her mother, allowed her to marry her supposed half brother. Reality check number one.
She freaks when she sees him. She freaks when she sees her daughter - oh no the genetic dice roll!!! She freaks some more when she finds out that in addition to one possible genetic oddity, she has three. Triplets: one girl, two boys. Yep, one trope is still in place, the incredibly magically multiplying sperm of a Harlequin Italian alpha-romero hero. I guess we have to toss in the magically mutliplying eggs of the h if I recall basic biology. (I jest, but it may be true. We have Italian-American friends from New Jersey. Her maiden name is Santorelli; married name is Travaglia. She knew, KNEW, she was having all boys as there are no girls on her husband's side of the family dating back seven generations! Seven! Gypsy curse maybe. Anyhoo, back to our Italian.) She decides to stick around with her husband brother, but doesn't say why she's giving him the cold shoulder. In all the different ways she can break his heart, she picks door number two. Why tell him the very reasonable concern that they are half-siblings when he can just think she either doesn't love him anymore or possibly found someone else? Hmm. Even the shrink tells her to tell the H.
To add more examples to how big of an idiot she is, she fires the nannies as she wants to be the acting mother. Hey, I am not a nanny fan unless they are the h, but triplets! You need help girl.
Big misunderstanding is cleared up from an infallible source. Is the infallible source DNA? No, it's Aunt somebody. Heavy sigh.
Yes, as many reviewers have pointed out, it was sweet they loved each other. The hero is a keeper, but I prefer active brain cells in my heroines.