College dating

So, there’s a guy, I been dating in a fraternity, recently find a picture of a girl in his phone with her talking dirty, and question him bout it, and he tried to blame it on his fraternity. He had the girl in DND, so the message wouldn’t pop up. We haven’t talked really in over a week, just text, and a hey and bye on campus. At this point , idk where we stand? I have just been doing me, but everyone keep saying I should just ask and don’t assume, what y’all think?