Deb - 1) I DO think finding the rings was a good omen
2)
Quote: "I'm working on letting go"
He probably thought you meant you were letting go of HIM instead of letting go of the need to control the sitch.
3) DO go with him Friday. No ifs, ands, or buts. He needs your time and attention, more than you might realize. Go and ACT AS IF and be darned good company (and wear some Victoria's Secret).
4) DON'T bring up the OW's birthday or her present again. If HE brings it up, just say "look, I'm sorry I brought that up, I really don't think we should talk about it now. I KNOW you are ending things with her and I trust you to get it done without hurting me any more". (Wording here is VERY important - you KNOW he is ENDING things (ACT AS IF) and you TRUST him to get it DONE without HURTING YOU MORE (which reminds him that OW's feelings are not the only ones that have been hurt)).
Be SURE he can't find out you've been calling lawyers (I would not call from the home phone).