My ex ruined my life and I still can’t get over him 2 yrs later. Why?

Why can't I get over my ex even though our relationship was horrible? Trauma bond?

My ex was my first boyfriend and, to this day, my only actual relationship. Our relationship was extremely unhealthy. Because of that relationship I ended up going to jail, started using substances, got cheated on, and went through a lot of things that I know were terrible for me.

Yet for some reason, I cannot completely get over him.

I've dated other people and had long-term situationships since then, but I always
end up comparing them to him. I can go weeks without thinking about him and genuinely feel like I'm over it, then randomly the memories hit me and I miss him all over again.

The weird thing is, I don't even see myself getting back together with him. He has a girlfriend now and has had other girlfriends since we broke up. He similarly the type of person who can’t go very long without being in a relationship. But sometimes I still wonder if he ever thinks about me the way I think about him.
I think part of my attachment might come from how intense our relationship was. We were constantly doing reckless things
—sneaking out to see each other, stealing our parents' cars, running from cops, etc. I experienced SO many new things and "firsts" with him that I wonder if my brain associates him with all that adrenaline and dopamine.

We also have a mutual friend, and whenever I see her I catch myself trying to get information about him. Deep down, I even hope I'II randomly run into him.
I can't tell if I actually miss him, the intensity of that time in my life, or if I'm still attached because he was my first love

Has anyone experienced this with an ex? Could this be a trauma bond, and what actually helped you finally detach?