More thinking, still no answers

Clearly, I have a problem letting go of certain things. So it's not surprise that another woman would be a real challenge. I've spent so much time thinking about the situation lately. I don't know what I want from him. I know he's sorry. I know he is. I'm not really worried it will happen again. But I can't figure out what I want...what I need to happen in order for this to go away, or at least subside. I don't want him to contact her. I don't want to contact her. Maybe I just want more of my questions answered. I honestly don't know. It's not like it can be "un-done". He can't take it back. The options are to either accept it and work through it or leave. And considering we've been back together for over a year now, it seems silly to split up over something that happened over a year ago. I just don't know what the hell it is that I need to move on. Is a partial elective lobotomy an option???