Harrier,
I definitely don't want to scare you, I just want to make sure you are aware of warning signs.....Does she tell you when she interacts with him? Thinks about him? I guess I would defer to Sandi, or someone else who has made it back after an affair as too what they would think of continued contact with the affair partner. It sounds like your hands are tied in this situation, so your hard stance of if you cross the line, IT IS OVER maybe is the best you can do. As far as telling you I told you so, it's not my style. I want you to be a success story.