Wow, I,ve read some things on here but this kind of takes the biscuit. You pointed out that this woman who you have never met appears to have narcissistic qualities, and encouraged him to have therapy because of the toxic situation at home, and through that it enabled him to reinforce his boundaries with her more.
That poor woman has no idea what she's dealing with, does she, or maybe she does ?
You've tried your hardest by the sounds of it to win the pick me dance and still you lost, really poor behaviour.
Your affair partner is a selfish cruel man, if I were you I would run, the man's an utter bastard, he's clearly got you and his therapist feeling sorry for him, a master manipulater.
The truth of the matter if I were to guess is that he is the narc, he will not leave his wealth or wife, this kind of man wants it all, and the past two years I would bet he has had a number of women on the go but believes you've been shelved long enough and fancies another play.
He's not a coward, tell him you're going to tell his wife about the renewed contact, I think he'll show you he's no coward.
I hope you never left a decent relationship for this man because he sounds like a bad un.