Should I be concerned?!?

My boyfriend and I have been together for almost 9 months. Well he hasn’t been in the mood for me really unless I say something. But usually when I say something he still don’t want to and waits days after we talked to actually want me. He says it’s his testosterone levels but yesterday we were at Kennywood and idk I went through his phone while he was on a ride and saw this girl on his snap that he added 2 days prior. They haven’t talked yet but I kinda got insecure about it. Do you think he just doesn’t want me or do you think it’s just something going on that he can’t control?🤷🏽‍♀️