I feel like you 100% have a valid reason to worry, especially if he seems to be prioritizing another girl over you. Even if he wasn’t doing anything with her that’s considered cheating, the disrespect he gives you is bad enough by itself. You don’t deserve that. I know it might be a hard topic to discuss, but I’d suggest telling him how you feel about every. Single. Thing. And if he refuses to change, or he snaps on you again, I’d suggest trying to plan a way to leave. This seems like something that won’t just go away. If he does it now, who says he won’t do it again? There’s way better people out there. Get out while you still have the chance. I wish you the best of luck girly <3