Another thing I wonder about is family involvement. We might be close to let her family know/can't hide it any longer. (Family is big, very loving, very high values). What's the procedure on that? I'm sure she won't tell them the whole truth like she didn't tell me. Should I play along or meet with them before/after very confidential, with no blaming, understanding and love and let them know the truth?
Let them know lightly that you guys are going through problems related to infidelity. Do not try to get them to help you out though, so just let them know in case things get further out of hand and leave it at that. In the worst cases the families will support the cheating and will dog you out badly.