Well, that's not entirely accurate. He has spent the last two years trying to be nice to her, but if he gets anywhere near her hackles go up and sometimes her reaction is borderline violent. She will sometimes let him pet her, but even after him doing this repeatedly (two years, but on an inconsistent basis because we didn't live together) she hasn't let her guard down at all. So understandably on his part, he's a little fed up with the whole situation, and it would be more fair to say that he can sense she isn't too fond of him. He never did anything to purposely upset her, and has made an effort to show her he's her friend, but she simply refuses to "forgive" him.

I do feel guilty about "banishing" her to a room, but if I let her out she makes a beeline for the bedroom, hides under the bed indefinitely, and poops there which is really difficult to clean up. Either that or she hides in her litter box and gets filthy. So, this seems like the best compromise for now, although it isn't ideal.