I would also agree with 25 on this. I'm new to the forums, but I've been living in the spotlight of my wife's MLC for over a year now. From your text's above it looks like he's playing victim and you sound a bit encouraging by apologizing for what he's done to you and your D.
He chose to leave/step out of the relationship and not work on it with you so I fail to see why you should have to apologize for anything. You apologizing seems like it makes him feel better about what he'd done and that you still desire him.
Seems a bit silly saying that seeing as how I may not hold any hostility/grief towards my wife anymore, but I do see a future together. Maybe I'm in denial because I'm not hopeful as much as I am sure of this. I guess I kind of see my sitch as preparing the both of us for when both kids are out of the house. I'm learning how to be a partner and she's learning how to cope with accepting growing older. It's the acceptance part that gives me the confidence that we'll be together in the end.
I would agree your situation is confusing since actions speak louder than words, but the loudest action I see the most is that he still lives with OW. TAMF - I don't think you owe anyone an apology.