Bf goes over to friends house every night.

I don’t know why it bothers me, but it does, My boyfriend will go over to his friends house every night now that it’s summer and most of the time he doesn’t even tell me. We don’t live together or anything as we’re only 17 but it still gets on my nerves for some reason?? I feel like I’m just jealous because his friend gets to spend more time with him than I do if that makes sense. ugh has this ever happened to anyone else before??