Yeah, twice......she cheated with the same guy both times. I hung around for 10 years after she did it the first time. Eventually ended up playing AH a LOT, and she brought that up when we were drawing up the divorce papers. I told her I had in fact played AH alot, it was my escape from the BS she was dealing out in an effort to deflect guilt from herself for being the cheater.
In the end, I knew it was for the best that we part ways. My pride was hurt by her cheating, not my heart.
She married the mutt, and now, not even 5 years later, she is doing the SAME THING to HIM: Suddenly has feelings for a guy she met online, moved out, yadda, yadda, yadda......rinse and repeat.
There are times to swallow your pride and try to make it work. There are also women out there who will not be happy no matter who they are with....once they decide they are not happy, they start looking; once they find someone else, and know they have a place and someone to go to, they leave and then make "excuses" for cheating and leaving.
It's up to you to decide what you are gonna do. In my case, I tried to forgive and forget.......it was she who never forgave herself or gave up on being with the guy, and I lived under constant scrutiny and accusation for 10 years after that.
NO ONE is worth that. Have a heart to heart with her, have a small digital recorder with you and talk things over......tell her you just wanna know the truth so you can deal with it......then make sure you have it on record if or when she starts coming clean or confessing. (In TX, that is legal, don't know about other states. As long as it's face to face, you can record everything without her knowledge, in TX that is)
Then kick her to the curb. When she accuses you or AH for her own cheating, don't get mad.....just be calm and respond that playing a game is not infidelity. If it goes to divorce court, play her confession (you did remember to turn the recorder on, didn't you?) to your lawyer. Let him/her handle it from there. Unless your attorney says it's okay, don't talk to her anymore til the final hearing is over.
I sound extreme, I know, but having been there and done that........you are better off without her.
I hate to hear that you are going through this, but in a year or two, you will look back and wonder how you missed the signs and realize your life is better without her in it.
My 2 cents............