I'd like to say that you aren't right but I know that you are. I did struggle a lot at first but I guess the deeper in I got the easier it was to not listen to that part of my brain.
I never thought it was her fault. More a case, at least in how he presented it, as people who weren't actually in love sticking together for the kids. I am aware that that is a likely story. He has always made sure to say he thinks highly of her but I know how that sounds given everything that ha been done. She hasn't had to move out, she is still in her same job.
He is good with his kids. He still sees them pretty much everyday. Whatever is in him to lie, etc to people he loves doesn't extend to his kids. Of course, cheating is hurting them down the line.
I believe they were going to break up anyway but I am sure that there being a 'me' (whether that was that was because of love of because of him having a place to go) helped to move things along. None of which makes it right.
Perhaps that is part of why I am so anxious to make this work. To somehow not have done something morally wrong for no real end result. I don't know.