cr995, you've spent decades being gaslighted. No wonder your head and heart are all twisted up.
I can assure you he is not Mr. Wonderful to the new victim. Sure, things may be ok at first but no one can maintain a facade forever.
Here's what I learned from my alcoholic friend...they hate being alone. She would find the most rotten losers and move them in with her! They would sponge off of her and treat her poorly, all alcoholics themselves, and she would allow it to happen, even if she didn't like them very much either. She told me she just didn't like being alone, so even being with a loser was better than that. And trust me, she wasn't feeling anything for these guys - there was no emotion involved whatsoever. She was drunk all the time; she felt nothing but anger on a regular basis.
Thing is - you are buying into the fantasy that some other nice lady is getting what you were denied. Stop doing that! Accept him for who/what he is, and when your head goes skipping down that fantasy lane, don't let it wallow there for long. It's not real.
What was hardest for me was accepting the parts that weren't real after all. I was pretty angry at myself for a long time for being - well - so stupid to not see the forest for the trees. But once I found forgiveness for ME, and a certain amount of gratitude for the lessons learned, I was able to let go of the hurt. It really doesn't hurt anymore now. Sure, sometimes I have pangs, but they are few and far between. I know my reality, I accept it, and I know when I am fantasizing.
"As we think, so we are". Change the way you view all of this, accept reality for what it is right now. And you may find your thoughts about him and his new "life" change right along with it.