He has a girlfriend

So there is a new guy who came to my highschool. He is cute and we have talked a few times but I am not really super interested in him. My friends though see us as a cute couple because they are all obsessed with me getting a boyfriend. They tease me all the time and the guy has a girlfriend. I am starting to get really embarrassed because they talk about him when he is standing a short ways away. What do I do to get them to stop and get that I don't like him.