I can't let him go

My ex and I have had an on and off had a toxic relationship since 2018. Our relationships never last long yet we can't let each other go. He's hurt me in the past and I've also hurt him. We've both had other partners but we still find a way back to each other. I understand that we were both really young (I was 13 when I started dating him and he was 15), and that we're attached. I'm not looking for advice, because I know people are going to tell me what I've heard plenty times: let him go, its not worth it. I choose not to listen to the advice, because as crazy as it sounds, I'd go through all the pain again if it means I get to call him mine, and I know it's the same for him. We're unhealthily attached, and I'm tired of hearing people say "just move on" like it's an easy thing to do. I'm done ranting now.