Zeph - I will be able to forgive her for the past. (I have basically already done that in my heart, because I realize how miserable I made her in a lot of ways.) The problem is not knowing whether the A is still ongoing. It would break my heart and possibly erase all the positive changes I've been making mentally and physically if I found out she was going out with me and then sharing time with OM. I don't know that I could forgive that - if this whole thing has been part of a larger deception.
Cindy, I'll take some time to read your posts. Just know that things turned around in our situation almost immediately after I took control of ME, and got to a realization that I can only control ME, and not her. (That sentence has a double meaning by the way - I can't control HER, and SHE can't control ME either.)
Get yourself to that point first. I don't know where you are right now, but if you can't wake up in the morning and be OK with not talking to, texting, hearing from your spouse, then you're still at square one. The only way to get there is to start reading and talking to someone like a IC.
I'm here if you ever want some help. (But I'm not great at all this, and may not be of significant help. Like I told someone else. I don't know how to fix a marriage, but I've gotten really great at fixing ME.)