I can only offer my condolences and feel for you man!! When I entered into marriage with my wife, I made sure that I was completely commited to a lasting union. There is no room for doubt in a marraige, no room for question of integrity, and no room for former "friends" from facebook. His lack of integrity is what would really anger me. To not respect the feelings of both parties in a relationship is as much unacceptable as her actions. She doesn't respect your feelings and neither does he, and if they don't now, they never will.
Take care of you and what's yours, do not concern yourself with whats hers. She is not concerned with you and your feelings and never will be. Don't take any time to feel sorry for yourself, but instead feel sorry for her, she's the one who will lose in the long run. You still have your kids, your family, and your friends here at FABO, and all the support you need can be found in these circles. Good luck man, you will come out on top of this and that's a good feeling to know!!! Geof