"Once a cheater, always a cheater," isn't necessarily true. It has a lot to do with age, which is another reason why it shouldn't be legal to be married until you're 30. I was married at 19, and time and time again, I see people getting married young, and divorcing a few years later.
Either way, keep your space. She is saying she doesn't want to live to flip the script on you. She's playing the sympathy gig.
Good luck, it's not easy. Go find yourself a good rebound.