Crossing boundaries?

Princess
Alright so I need some honest opinions about this: I've been with my boyfriend off and on for three years I love him very much the problem I have is that he has a best friend who's a girl sometimes I feel like I don't compare when it comes to how thier friendship is apparently they talk about anything and everything cuz today he sends me a pic where it was her and her gf in bed after being intimate the gf wasn't naked but she was I don't think that best friends should be sending each other shit like that what should I do? I'm kinda annoyed with him