Don't let some people tell you otherwise... It's ok for you to have cheating as a deal breaker... Whether it was from 5 or 10 years ago... The fact of the matter is she cheated. Now there are many reasons as to what she could have gone through, in order to cheat on you... You married young, she didn't have experience, you were away etc. None of these reasons absolves her cheating. Get a good divorce lawyer, cut your losses and move on with your life