Just give her the evidence, and let her deal with her family issues on her own. and be careful sometimes woman in these situations like to revenge f**k, and that might not be something you want to get involved with right now. or not.
might want to tell your wife you cant stand looking at her cheating face anymore and its best she moves out. unfit mother strikes a nerve. its time she faces reality.
the rest depends on how much courage, self-respect and Valium you have.