My boyfriend has been liking this other girl's photos?

[Faye]

So my bf is 17 and I'm 16. We've been together for a few months now. He's so sweet and everything, but the one thing that bothers me is the fact that he likes other girl's selfies and snapchats other girls. Regular selfies are ok, but he likes girl's bikini pics and generally provocative pics and it makes me feel uncomfortable. He also snapchats this girl who sends him provocative mirror selfies. I know this because we were hanging out and he was looking through his snapchat and he got one from her, and he said "oh, it's *her*" in a "she's so annoying" type of way, and I said, "open it." He opened it without hesitation, and of course, it was a provocative mirror selfie. I scoffed at it, and my bf responded by putting it on the camera, putting his arm around me and pulling me in close, and taking a pic of the two of us as a response. I thought it was nice, kind of like, "hey look I have a gf." But I don't know...I still feel weird about her. I mean, if he thought she was so annoying, why would he even have her on snapchat? Why would he "like" her provocative selfies on instagram?

I feel like I may be over thinking it, but I can't help but feel a little jealous and uncomfortable. I hate to be the jealous, controlling girlfriend, though! We've only been together for a few months, and I'd hate to start being so controlling so early. But I can't help but dwell on this and feel weird about it, and I feel like I shouldn't be subjected to that. Should I confront him on it?