In love with my best friend, can't move on.?

I'm in love with my best friend, a typical Twilight/BVB fan. Me and her have been close for 2 years and I've never been able to get over her. I've dated 3 girls since I've known her, and I've been asked out by one of her friends, but I never could stop thinking about her. There's just this thing about her. Whenever I look into her eyes and I see the green, the patches of grey and the gold ring arouns her pupils, I feel strong and exposed, and I feel like I'm floating almost. Thinking about her eyes just makes me catch butterflies. But the thing is, I don't like expressing my emotions to her, because she has a boyfriend. Thing is she's never met him; he lives in another state and he's a grown man. Her parents don't know about him either and her friends don't like approve. In fact, they wanted us together. But I back off because I know he exist. I never take her out. I never confide in her and I don't go to her house when she invites me anymore. I only hang if we're in a group. It's obvious things between them aren't going to last anyway. She's proven she's a bad judge of character. She assumed my 5'10, 170 pound man-whore friend she met over Facebook was a 5'1, 90 pound Yugioh enthusiast. And now she hates him because he "wasn't the guy [she] thought he was."

Most of her friends don't talk to her as much, and in her words I'm "the only one who cares". But, things have been pretty awkward lately. Fact is, I don't think of her in a sexual way. In fact, I tried, and I ended up laughing at the thought of her stripping for me. She's beautiful and has a nice figure, but she's not "sexual", which I prefer honestly. I always imagine us in a park, sitting under a tree and watching a lake during the sunset. But I digress, she's been acting immature lately. After I told her how I felt, she told me she didn't know if we would work out and I told her we should set up some distance, which she refused at first, but i got her to agree. And we don't talk as much anymore.