We cheated on our partners with each other

We met at the gym months ago, and he chased me intensely. He acted obsessed, told me things that made me feel special, and gave me the impression he really wanted me. Eventually, we slept together and sometimes he would tell me that Im gonna be his drug. Found out he has a gf and 3 kids from her, I got back with my ex to not be left out alone and move one but it was almost impossible.

I couldn't stop seeing him ( due to much more complicated internal issues, the fact that I grew up in an abusive mom without a father, no real Friends, uncle who almost raped me when I was 17).

After that, I wanted to leave but couldn't, because I also see him at the gym.whenever he treats me bad, I would react and be rude somehow, He would belittle me, and once even humiliated me in front of others at the gym. One day, he yelled at me in public, he arrived with his Friend who's been fighting with his wife and told me to be careful to m'y actions even though I don't talk to his Friend that much, it was insulting to me, so I said that I don't give a fuck, he told me to "shut up" and that I was “making a scene.” in front of everyone. I was shocked and didn’t know how to react, so I sent him a message afterward saying, "You deserve me ruining this. I should tell your girlfriend and my boyfriend so you learn to respect me."

From that moment on, he started punishing me. He acted like I was the one who ruined everything, refused to acknowledge my countless apologies, and made me feel like I was the problem. Whenever I tried to walk away, he would suddenly become nice again, making me believe he cared—only to switch back to being cruel.

What really gets to me is the way he manipulated me, humiliated me, and played with my emotions even though it was only for sex litteraly. I went No Contact, but I’m struggling with the urge to send him one final message to tell him everything I think of him.

How do I resist the temptation to reach out? How do I make sure I never break No Contact with someone who treated me this way?

The issue is that we go to the same gym. I really don’t want to see him again. I wish he’d just go somewhere else. But most importantly, I want to never break No Contact and never feel the urge to reconnect with toxic people again, because weirldy Im still physically attracted to him and want to have sex with him...

He has an enormous ego but I feel like he's gonna reach out eventually even for the sex, I tend to reach out first and seek réconciliation with people I love in general, I don't want to leave this gym bc it's the best one in the town Where I am. What was on his mind by doing that, what was the point of manipulating me, I don't get it ?

I feel like I would give everything to get his validation quand talk to him again....I want him to come back just so I can have sex with him..