I forgot the title and author name but it should be a series, not a standalone but when I first read it, only the first book was out.

H is a doctor and h is a psychiatrist. They met on a military camp in one of those middle eastern country. In short, they got together and settled down in America. But H got called back to the camp as he was really needed, so he went back. h decided to find a way to get back to camp to stay with H.

So while at camp, H became mentally unstable after one outing as there was an attack and he came back not himself. h tried to help him by using one of these trial medication (injection). h also tried the shot, book ending was her fainting in the end and not sure whether the jab was loaded or just a placebo effect.

I'm sorry if my post sounded like gibberish, I'm trying my best to remember all the important details. Any help would be greatly appreciated!

This sounds really interesting, did you get the name of the series yet?