My ex wife cheated on me while I was in Afghansitan. Rumours have circulated that she also did it with other soldiers. I have no proof of this however it does not matter as we are now in the divorce process and have been apart for over a year.
So coming from experience, go to a Padre ASAP, if you havnt already. They will best be able to guide you on this issue. From personal experience, they get **** done. Get a lawyer. This is your own decision to make, but once a cheater always a cheater in my books. Get that lawyer, if there good, because of her adultery, she should get the short end of the stick.
You don't deserve that at all. You sound like an honest decent guy, and judging by your reaction to this you are. You can do better than this wh*re. Trust me, again from experience, you will find better and be way happier than if you try to work things out with her. Keep in mind it takes two to tango. He may be a complete douchebag, but she played just as much of a part in this as him. If it wasn't for her this wouldn't have happened. DO NOT forget that. Get rid of her and find better for yourself. You deserve it.