That girl - Although I see so many similarities between our two sitchs, you are way ahead of my game. H left 6 weeks ago. Some interaction including Xmas, but not anything like yours. During 26 years, he also had an EA (always denied it as being PA) and also struggled with my weight gain (first from 2nd child, later due to health conditions). His current EA is with a coworker - he even commented to me about her being a little chubby when he first mentioned his new friend! Looking back I've spent so much time in the cycles you described (H appears to be MLCer), withdrawn then affectionate and me always looking over my shoulder to see if the previous OW was in the picture. The new OW side blinded me.
I'm not as young as you, but I have a lot to learn from your posts. I want to get to your PMA!
Fell, sounds like you've had some positive interactions too. Good luck to both of us and all others on here.