I always felt there is a business side and DB side of this. I had a bunch of emails and IM's saved (my state does have laws regarding affairs) that I kept safe. The reason being if she wanted to play hardball. As things moved on it became apparent that she didn't want to go that route and the papers disappeared. The truth being that it was business. I wasn't keeping them for vindication for unruly behavior on my part.
So beware that......the evidence will hurt. What you need to do is detach from it once you get it....put it in a place for safe keeping and forget about it. You can't let the evidence push you back....not good for you.