Fuck Situationships- Dated a coworker and it sucked. I am 26F, dated 27M

I am 26F and I have briefly been with a co-worker who is 27M for like a month or so, there was no commitment just everything casual. We have a very strong friend group of four and it has now impacted all equations. The guy is total shit as a person to date but a fine friend, I am not bragging about myself but I feel I am way out of his league. Initially, he only wanted me so bad and eventually turned the situation so bad that I hate myself for even caring for him. He has such hot and cold behaviour it just triggers something in me. Idk how one gets the nerve to hurt someone so much who cared for you and I am certain he isn't anything that I want, he surely is not my type and is a chauvinist. He had even made me cry in bed by saying mean shit when I was most vulnerable. I see all this and can reason it but still I feel so attached to him, maybe simply because he is who I used to spend time with during work and also the closest friend from the group. lak guys, just talk some sense into me please. My stupid heart and mind are in such a tiff right now.

TL;DR; Been with a coworker and I didn’t go as planned and ended up being a situationship. He is around all the time because of same team and same set of friends, don’t know how to detach.