think I’m crazy

Last semester my boyfriend had a class with this girl who he says he’s friends with and this girl openly cheats on her boyfriend and he knows about it but he still wants to be friends with her. So they would Snapchat about random things and play iMessage games all the time (which is something that me and him used to do all the time before we started dating).

She has a bf now but I was uncomfortable with it as I think anyone would be and he knew this so he said that he would stop initiating conversation.

BUT this semester he doesn’t have class with her and the day before Valentine’s day I saw the text messages of them playing iMessage games. He sent her the first message.

What do y’all think? Would you be mad?