How do I leave a toxic relationship?

This is gonna be a long story.

Me and this girl who I won’t name met in march. She’s so beautiful and breathtaking honestly so when her friend told me she liked me I felt really good, a week later we started talking and we ended up getting together. It felt so good at first she would reassure me and love me and be loyal to me, she blocked her ex’s for me it felt perfect and then in May things started to go downhill.

She said she wanted a break because she wanted both of us to work on ourselves and we ended up not taking it and then the week after that discussion things felt even better it was literally the best week of my life and then she suddenly got all dry and distant and blamed it on me and then the next month I save her from suicide and I helped her get professional help.

She cheated on me 22 days later.

I got helped her even after we broke up and I got back with her.

I regret that.

It’s been a month since we broke up I probably could’ve gotten over her by now actually I don’t know but she still doesn’t treat me that good and we just argued because she wouldn’t block her ex saying “we have a strong past” “he was just complimenting me” when he said “U sooo fineee 🫦” and I cried so much from it and when I told her how it made me feel she said “I’m sorry but I won’t do nun” and she even admitted to having “hoes”

I still don’t wanna leave.

And my cousin and my friends even her friends are saying we should break up, one of them said “look yall cute tg but I don’t think you guys are meant for eachother because something always happens” and my cousin is telling me it’s best if I leave and my friends are saying that too but she’s so beautiful I know looks aren’t everything but for some reason they kind of are because she’s lucky she’s so beautiful if not I would’ve left her a long time ago. I hate the fact I can’t leave and I feel like a clown for it. And it got to the point where basically everyday she does something that gives me some sort of stress and sadness, and I cope with that from my trichotillomania )hair pulling) and watching 18+ material. It does help but it shouldn’t have to be that way.

What if the best way I can end it with this girl, I need help with this so badly.