How do I get over my FwB whom I like for four years (who doesn't like me back)?

We met four years ago and slept together. The sex was very good and it was actually the best sex of my life so far. I was attracted to him for no reason, really. I just feel so attracted to him, not only sexually but emotionally, physically, every inch of him.

He started talking to me after, which was something I wasn’t supposed to do because I don’t want to know him and have my feelings involved in the process of sleeping around. But I fucked it up, learned things about him and realised how much I want him in my life. I understand his inner issues, I would love to read his poems, I would love to hear the short stories he makes, listen to his activist rants, take long walks with him, everything. My feelings were swirling around, there were butterflies inside my stomach, my knees were shaking.

He didn’t like me. I just knew it. I can feel it in my bones, it hurts so much. He had relationships, then broke up with every one of them after. I started dating a guy and I tried to remove him from my life. I think of him everyday while I’m with someone else’s arms. We talked throughout the 2 year relationship I was in, but then my feelings would overflow and I would withdraw myself and try to remove him from my life again.

My relationship became emotionally and physically abusive. I broke up with my ex. I can not lie, I am still thinking of him.

Last week, we met again after four years. My feelings are still overflowing. My heart, it’s fluttering and my legs are still weak. We drank together but no we did not sleep together. I still can’t deny my feelings for him. We talked that night and he told me that we can’t be together because we’re dangerous together. Because we’re both hurtful and careless people, he said.

My heart is aching.
Please help me what should I do to finally accept the fact that he won’t like me, and move on?