How do I not let sexual tension interfere with a friendship?

I 'm a cancer and my friend is a taurus, so we are naturally kind of attracted to each other and have chemistry, but we're not compatible in other ways and I don't want to get into a relationship with him, but he's a great friend and makes me feel secure. I am afraid I am hurting him by saying I only want to be friends, and i've explained to him that its not because he's unattractive, just because I don't want to get myself in trouble. He keeps coming back and can't control himself, tries to make the moves on me etc. and I gently and kindly let him know that he's making me uncomfortable. So I would like to know, is there any way I can not let this sexual tension interefere with our friendship without hurting him?