Am I wrong or is he?

Hey everyone,

Last night my man went to a party where everyone was drunk. There was this girl he knew from years ago there and she told him she wanted to hook up.

He told her that he already has a girlfriend but she kept texting him last night all the way into today(they were recommended friends on the app a few months ago so they added each other but haven't talked until last night.)

I don't doubt his intentions but I know hers are different so I told him I wasn't comfortable with him talking to her and he just kept telling me to stop tripping but when I got upset he told me to stop behaving this way because he was just messing around. It's not so much even her at this point but the fact that he has been continuously disregarding me and then tries to brush it off with that he was just playing.

Am I over reacting? We aren't even talking now but who's in the wrong here?