How do I deal with mean kids in school?

So my ex boyfriend and I are still really close friends, but everyone at my junior high school thinks we still like each other as more than friends and we are going to get back together. This is not the case though, we are very close friends and we have agreed not to be any more than friends because it would ruin our friendship. So, kids at my school are cruel. First of all, you should know that I am a bit darker skin colored. I am actually white, but for some reason, I am very very tan. Kids think I am asian. They make fun of me for it. Not to my face. But they tease my ex about it all the time. They call him John Lennon (because of Lennon's wife). They come up to him and say things like "Hey, I hear you have a thing for asians." and "why did you go out with her, she looks like an asian depressed camel, you could do so much better!" and "she looks like a dying deer, you can do a whole lot better than an asian!" When I hear them say these things, it really hurts. I can't walk the halls anymore without feeling their eyes on me, watching me, judging me. I know they all think I am ugly and they are convinced I'm either asian, indian, mexican, brazillian or something. But I am acutally white. I try not to let it get to me, but sometimes I just can't take it. It really hurts, and I don't know what to do. Please, any suggestions? Thank you.