help, I've developed a crush on my friend/coworker! *edit*

So he was one of my first friends when I started working there. We've hung out everyday at work and recently we've been messaging away from work (talking about work, music and tv shows). We like a lot of the same things and I feel like I'm developing a crush. Big problem, we're both taken. I don't know what to do, I can't stop thinking about him. Advice, anything?
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*edit*
Just because you develop a crush, doesn't mean you don't love someone. What I'm asking is how to stop liking him. Not "how do I have both". I understand that I have some feelings towards a person that likes the same things I do. I'm not asking how to get him, I'm asking how to stop liking him. Jeez, rude.