Help me make sense of this I’m losing my mind

I’m in a really bad place right now. Was in a relationship with a manipulative guy to the point where I felt like I wasn’t good enough and more so like if I was crazy. He’d call me names or say things in anger. He’d flip a situation where I end up apologizing and sometimes I’d ask a question and it doesn’t really get answered, he’ll give me some technical justification which feels like the answer but when I think of it. It’s not it.

I decided I can’t do that anymore so I just became silent and stopped speaking to him because I realized behind my back he started seeing someone else also.

Only thing is which do I feel shitty? Like why do I still want him, want to try to make it work etc.

like I’m not happy. This heartbreak hurts extremely bad. I feel like I’m withdrawing from a drug. Most days I want to message or call him. Like why was it so easy for him to move on?

I’m left feeling like I’m the problem 😭😭😭😭