Why do I get aroused everytime I think about my crush?

I've liked this guy for 2 years now and i try to distance myself because he just TURNS ME ON, a lot. doesn't matter what he does, even when i think of him. Is something wrong with me? (also its not an obession because I like him as a person not just because he's handsome, it really has nothing to do with his looks)
Why do I get aroused everytime I think about my crush?
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