Can't stop sleeping with my ex
I've been with my ex for about a year now, things were going great except there were a lot of trust issues in the relationship( I didn't trust him because I've been hurt sooo many times). Recently, we broke up because he was texting a girl that we work with late at night. If found out that they had a crush on each other and decided to break things off immediately. Now we still live together and he used his "hurt" and "anger" towards me as an excuse to seal the deal and start sleeping with this chick.
I've tried kicking him out, ignoring him, I quit my job so I wouldn't have to see either one of them, but nothing seems to work. He refuses to move out because he has no money saved. However, in the meantime I keep allowing him to sway me back into the bedroom saying that he misses me and wishes he could take it all back, even though it makes me feel bad and I'm extremely scared of catching an STD, I keep going back to him because he's the only man I want to be touched by.
I try to stay away but he keeps roping me back in, I feel completely helpless and so alone. Even on nights when I try to stay with friends to avoid coming home, he's in my heart and my mind. I can't eat, I can't sleep, I can't function, but he acts like he's doing just fine. I know that if he actually loved me he wouldn't have slept with her in the first place, but for some reason I keep kidding myself that we still have hope.
What can I do to avoid him and to get over this pain? It's extremely unhealthy and I'm scared for myself