Tangled I have wrestled with this problem myself over the last couple of years. A friend attacked me out of the blue - she knows she was in the wrong but can't bring herself to admit it. She went so far as to justify her actions with mutual friends (who know the real situation - she has history). Long story short, she won't apologise and because of that I'm still angry although I would have forgiven her right away.
So where does that leave me? I can forgive in one sense, that I understand she lost her temper, but I can't pretend it's ok and I don't want to be around her.
With your AH it's a lot simpler to maintain the anger because he's still behaving like an AH. You're probably going to keep getting angry for a while until he loses the power to push your buttons. I'm pretty sure that day will come, just not right away.