I’m feeling self conscious...

My bf and I have been together for a year and a half. We’re 18. I kinda feel self conscious about myself when I think about the girls he liked prior to me but never had the chance of dating because they all friend zoned him. He would occasionally look up their Instagram profiles and what not and that made me feel like looking at me isn’t really good enough. I don’t think I’m all that pretty, especially without makeup on. Idk how to stop feeling like this and worrying that he may like other girls more than me :(