What do I do??

Okay so this guy and I were friends and we ended up having a one night stand while he was talking to a girl, we later agreed to not say anything to anyone and I ended up telling my close friend bc it was at her house and out of courtesy I needed to tell her because of the clean up and what not. Long story short my “good friend” ended up telling the whole school and now the girl he was talking to found out and they resolved it ig but he was absolutely pissed at me. And I felt that it wasn’t my fault, it was his for cheating and not letting me know he was with someone... so he recently texted me and starts going off because someone told him I was talking shit about his now girlfriend, but I wasn’t and idky but someone is making all of this up, I tried explaining that I’m telling the truth but he won’t believe me.

he’s being really rude ab it.