Ian’s life has been hard. His childhood was hellish, and then he lost his wife and daughters. He was hurting bad, trying to drink himself to a grave when he met Marca. You could say that she changed his life. Their affair, short as it had been, made him want to move on, continue with his life. So, he went back to his job, being an ATF agent. He though about Marca a lot, but never let himself believe he will meet her again.
Marca life was changed as well. Ian got her pregnant with triplets! She settled down, was dating again, when Ian came back to her life. Now she's faced with all the feelings she tried to bury for the last 2 years.
It's a good story, but the suspense part was a bit too obvious. I guessed (correctly) the identity of the bad guy almost at the beginning, the ending a bit too dramatic and overblown. I just didn't like it.
On the other hand, we have Ian. He is still deeply scarred by the death of his daughters, and he doesn't let himself care for his sons. At least he tries not to. I loved the scene when he was alone with the boys, it was so cute. :-) Just one thing was a bit off, his plans to leave both Marca and them. He probably wouldn't have done it, but he hurt her with his refusal to commit to not her, but the boys.