I agree, it's different for everyone because everyone's situation and circumstances are unique. It's been not quite 3 months since I find out about my H's A. (it ended the day it was discovered) and for the most part I am doing pretty well. There are always up and down days of course.
The most important thing is that if you chose to forgive him, you have to really try to not throw the A in his face during arguments, fights, whatever. I know this is SO hard, trust me. But in order to rebuild your relationship and your marriage, you can't do that. I am not saying you can never discuss with him your anger and your feelings you still have, but you need to do this when you too are just talking not during a heated argument.
I am glad to hear your H is really trying and wants to make your marriage work. Keep remembering that part too. He made a BAD decision and a HORRIBLE mistake. You need to focus now on your marriage, the two of you and what he's doing now. Make that your focus.
If I am having one of those days and I am especially touchy/grouchy - I may say, "I'm sorry honey, it's a "bad" day". He knows, because we've talked about it, that means I am having a tough time that day and thinking alot about what he did. He then knows to not let things get into an argument or to just help me out more that day to show he cares and that he is sorry. Or he will give me extra hugs that day and throw in some extra "I'm sorry." We don't discuss it all day long or anything like that, he just knows. This helps me to let go of any anger that may have been building. When I can see how much he is trying, it me to let things go.
I know if you analyze, it doesn't seem fair. But for many years in my marriage I held resentment for trivial things and look where that got me!
SO, I am making a concious effort to not harbor the resentment for the big things either. Good People make bad mistakes. It's what they do after that matters.