Being a bitch?

The other day my boyfriend and I were talking about other people and he mentioned that he gets jealous of my friendship with my best friend (a guy) and he would prefer if I didn't be so pally with him. That is fair enough.

But I get jealous too. Today he whipped out his phone and showed me a few screenshots of ugly pictures of his friends (girls) to make me laugh but it only made me feel worse. I think it made me feel bad because he always tells me he doesn't talk to other girls that outside of school, but these were screenshots of Snapchat. Now I'm starting to get jealous of his best friend who is in his year (I'm a year younger) and i don't know what to do

I know I have to talk about it but I dont know how. He's going on holiday in two days and I won't see him for two weeks, or be able to communicate with him for the majority of that time.

Can someone please help?