Alright RSF---You REALLY have to shake this off. You HAVE to stop thinking about that relationship. It is soooo much bigger in your mind than it is in hers. She was told by you to move on. She was told this by you via your actions and your words....so guess what? She did.
That's where the respect part of this comes in. You got what you asked for. She didn't just up and leave you and go find this guy....you left first, so this respect stuff....blah, shouldn't play into it. I would be different if you were together and she has this affair....but it's not an affair. Yo broke up, she moved on, now you're fighting for your marriage. I actually respect you quite a bit. So forget those thoughts.
Stop thinking about it. I know, it's sooooo hard, but you have to.
If you want to call her and see how she's doing, then do it.
I think it's possible to work yourself into a tizzy and that's what you are doing. Call her and just say hi so you can freaking relax.
