Oops need to vent. Also advice? If any

I slept with my ex boyfriend while talking to someone. Not justifying my actions but we were in an argument and not talking, hadn’t talked in a couple of days. Meanwhile my ex was there for me and one thing led to another.

We are currently not talking anymore for other reasons. However, he found out about me and my ex and i understand that it hurt him but he’s been extremely rude and saying shit. And it’s not like I can avoid/ ignore him because we work together (-: But i am a manager and he has been disrespectful & making comments and i just wish he would let it go.

He can hate me all he wants but I feel like he’s being childish. We weren’t exclusive & he purposely would try to make me jealous with another coworker which was the reason we stopped talking.

Idk what to do, work is becoming not a safe place because of his behavior.