Boyfriend called me whore

theres this lesbian girl at school. It was like 20 degrees in the classroom so she offered me her jacket. I was FREEZING so of course I said yes. My bf gave me a phone check and read these between me and the girl.

Then threw my phone HARD at my leg, and called me a whore. Then stormed out of the room and has been ignoring me. He then left the apartment. I called him multiple times until he finally replied. I asked why he was acting like this.

And he said I was basically a whore and that he bet there was more going on with me and this girl at school. And he’s saying that this is something I should have told him.

I haven’t interacted with this girl AT ALL. I don’t understand him. We’ve been dating a year.