Normal to want to have sex with my good friend?

She’s a sweet Asian girl whom I’ve known for 2 years. She is incredibly nice and does things most girls wouldn’t do to strangers( in the sense of not being related) For example I had some food on my face while we where talking, and she used her hands to wipe the food off my face !! I was so stunned when she did that because no girl I’ve known would ever do that! Well that’s one of the many reasons that I like her. The thing is she doesn’t see me as anything other then just a good friend, and she thinks my mentality is the same. I now have thoughts of having sex with her( she’s also very attractive). I can never bring myself to telling her this myself because it might ruin our friendship... I feel like a sexual maniac. Might I add that she also has a boyfriend..