I am approaching this with sense of selflessness. I am going to try to show her compassion. She is hurting and needs help. As her husband, I need to give her one chance to come back. It's up to her if she wants to return or continue to be lost. She will always been the mother of my child(ren) and no matter what, we have to be good co-parents. That has to be.

I call bullshit, and there's a good chance she will too. Human beings are excellent bullshit detectors. It's easy to be selfless when it benefits you too. Tough love is much harder to do since it hurts her and deprives you, but I'm telling you it needs to be done... or you need to make that impression at least. Human psychology is a bitch. She will not value you if you do not value yourself. Don't "take her back" too easily. In fact, let her go. If she cares enough she will ask to stay, and you can work it out then. If not, then at least you know.

Ask yourself: what woman wants to be with a man who thinks that she is so great that he'll stick by her even if she betrays him? You are the prize; not her. Once upon a time, you were the hot shit and she wanted to be with you, not vice-versa. You owe it to yourself to man up and go off on her a little about how disgusted it makes you feel, how deeply and utterly disappointed you are, and how you can't believe she was selfish enough to allow you to go on for all these years watching the relationship deteriorate thinking that it was somehow your fault, and trying futilely to save it while she was actively throwing it away. Ask her to give you back all those years of your life, your love, and your dedication you wasted on a woman who didn't want it anyway. And seriously, think about it yourself, because from an outside perspective cheating is always fucked up, but from an inside perspective I'm sure the only thing you want right now is for her to be sorry and to want you back.

Anyway, I digress. By now after that little tirade she should be feeling a massive guilt trip, or else she isn't human. At this point you can do what you want... I'm no expert in these matters. All I have is a little insight into human nature, perhaps from having gone through similar experiences before. I hope you seriously consider my advice. Also, if you PM me your e-mail I'll send you a short document to read that hopefully will open your eyes to a different perspective. Regards.