Thank you for writing to Just Answer.
I was glad to read that you played the adult, as it is very possible that you are the only adult in this situation. I think you have been a pawn in a drama that has been playing between the two of them for a very long time.
Here are the red flags I see:
1. She is immature enough to go get breast implants for a new man...and went ahead and did it even though he was very sick.
2. He is saying that she has a long list to answer, when in fact, her actions should have given him all the answers he needed.
3. He says he has been in this situation before, but obviously didn't learn from it.
4. You are right, he will be left again, and I would predict it will happen on a fairly regular basis.
5. One might even wonder (not know how large a city/town you live in) why he would take you for drinks at a place her best friend would be. I can't help but doubt that was a true coincidence. He probably wanted word that he was dating to get back to her to stir up the exact reaction he got from her.
The dating world is tough at 40, and I know you miss him, but I strongly feel that you have "dodged a bullet" here and were lucky to get out early before you were totally entangled in the dance those two are doing, and wasted more time.
I wish you all the best in finding a man who is truly free to be yours,