Why do i keep doing this to myself?/Pls give advice

About a month ago, i found out my boyfriend was cheating on me with multiple women, it hurt so so bad, and it still does honestly. Anyways, After i left him for that , a few days my coworker (that would always flirt with me but i would reject because i had a boyfriend) started talking to me, we discussed what happened with me and my bf and he invited me to come hang out after work, so i did. It was nothing more than sitting outside and talking. But as we hung out more times i ended up sleeping with him. I didn't regret it at first . it kinda made me feel better about the breakup, And because i actually felt like i really liked him and we had discussed being in a relationship before.

But then, he had a change of heart i guess, all of a sudden he tells me he isn't ready for a relationship and a bunch of bs about he doesn't trust women etc. So yes it hurt, But i accepted it because there was nothing i could do... besides what i tried- Which was to stop showing how i care so much.. i thought if i acted like he did, it would make him care. And it did.. for a few days only. So nothing changes between us we're still just friends.

What bothers me the most is that he tells me he doesn't want to be in a relationship, but yet he tells me i can't be with other guys , and actually got pissed off at me for talking to another male coworker, how selfish!

So after realizing that he's never going to change his mind about being in a relationship (and i decided i didn't wanna be with someone like him anyways) Someone he knows gets my number from a mural friend of ours and me and him start talking and he invites me over, and me and my "friend" were just arguing and he told me "i'm not your boyfriend remember?" So i made the dumb decision of going over there. And we ended up sleeping together for like 1 min before i say to stop because it doesn't feel right.

i felt so guilty , like i was cheating on him.. but we aren't even together and he doesn't want to be. So i know i shouldn't feel that way, but i just do. Why do i think that sleeping with other people to get over someone is gonna help me?! I just don't know what to do. Did i do wrong by sleeping with the guy that he knew? Should i completely leave my "friend" alone? Thanks!