This story was Angst, Infidelity and Reckoning on overdrive! So much of all of them. Very complex portrayals of the situation. I actually found Harry by far the least sympathetic character which is a rarity, and was a very interesting thing, given it was all from his perspective--it's strange not to respect, and to get frustrated by, the narrator in a story and I thought it was really great writing.
I actually really liked the way you portrayed Snape and Ginny, especially when they finally stood up to Harry and didn't let him walk all over them any more. Drawing the line and standing firm, no matter how much they loved him. And he did have a good relationship with Ginny that he was throwing away for his desires--I liked their interactions at the beginning a lot--a comfortable, fun, funny relationship--a lot to give up, and not an easy or sensible choice. But then it didn't seem like he really did have a choice if he were to be true to himself. And I loved that Snape wouldn't let him come until he really had confronted what his true self was.
Really great job, and a blazingly clear-eyed, non-romantic portrayal of a gay man in a straight marriage and what comes from that. You didn't gloss over anything, and it was difficult and rewarding.