Re: wife cant let go of other man or make a decision to stay or separate
No, you have not been working the 180. You have been working the "are you looking at me while I pretend that I'm not bothered" dance.
Be thankful that she has not ACTED LIKE she has come around. You would be back where you started. Work the 180 for YOU. You have to get your mind around your worth. You don't realize your own worth right now and it is hard because her actions are hitting you hard.
Stop glorifying your marriage and her. You said that you thought that everything was fine. I really doubt it. Perhaps fine just meant that so long as she was around you then you were happy. I'm not there, but I can tell you that overwhelmingly, those so called "perfect" marriages were far from it. Not that trouble excuses an affair; however, if you think it was all love and happiness, then you are idealizing your marriage about as much as she is re-writing it.
She's not awesome, great, or anything else spectacular. Neither was your marriage. Its true condition needs to be realized by YOU. Her true value needs to be realized by YOU. Your true worth needs to be realized by YOU. Who knows, once you get a handle on those things, you might be happy that she is gone.
My point is to start from a framework of truth in everything that you do and think. It may not make things easy, but they will be less hard, if that makes any sense.