Most Helpful Guys
Don't make it a direct and uncomfortable talk. Bring it up after a date or during some stupid thing you guys are laughing about and just hint the question. If he acknowledges (which 99% of the time guys do) you can have drop hints at your OWN exclusivity and he should get the hint.
Seems to me that you two probably should have already had the talk. Next time you see him try to figure out a time to have it. And don't worry about the Instagram girls. Just because he follows them on social media doesn't mean he's interested.
Most Helpful Girl
I don’t think it’s too early to have “the talk.” It’s a good idea to chat about what you want from each other, so you don’t waste each other’s time. It was early on in our dating that I had the chat with my boyfriend. I basically told him that I am a relationship person and if we are going to be taking it further physically or what not we would need to be in a relationship with commitment. We are loving together now over a year later.