Sex is a big thing to me and I feel like I ruined my self worth when I did that.

OP, please go to counseling. This isn't healthy. Just because you chose to have sex with another guy you weren't in a relationship with doesn't mean you're worth less.

I ruined everything. It was all my fault.

No, it was not. You were broken up and he told you to move on. What did he expect you to do? Just sit around until he can make up his mind?

he told me how he made out with a girl and hung out with another. He said he had intentions to have sex but changed his mind because he "couldn't do that" to himself. I feel like he says little stuff like to make me feel bad and compare what I did and how he would "never do that" to me. I also found a throwaway account on Reddit where he was asking for a FWB or sext buddy in the area. It broke my heart. He says he had no intentions on doing anything but at the end of the day, he still made the request and its hard to believe it.

And you still believe this guy? C'mon.