I'm in that same situation but I did some thinking and I followed a few steps and now he doesn't like her anymore and my crush and I are really close now. Step 1: If she already has a boyfriend that mean that she doesn't like your crush or else they'll be together by now. But just to make sure ask her if she likes him. If she does I'm sorry but your going to have to forget him. But...if she doesn't try telling her that you like him so if she breaks up with her boyfriend and she's in desperate need of a new one she'll know that he's yours. Step 2: Now that he know she doesn't like him it's time for you to go in for the kill. Flirt with him, get to know him even better and smile a lot. And whenever he's around ask your friend to talk about her boyfriend so he could hear and he'll know that she has a boyfriend and that she's in love with him. Once he hears that he might forget about her and move on. (Boys aren't like girls they don't get heart broken and give up on girls they'll move on.) Step 3: Now that you're friends thouch him one his shoulder now and then(NOT TOO MUCH!). And whenever talking to him look at him staight in the eyes, even his looking into his eyes makes you melt(eye contact asures him that you're interested in what he's talking about.) Also laugh at his jokes. Step 4 (It's the last one!): Once you guys are really close friends escape the friendzone immediately. This means you have to treat him like a family member, which means you could talk to him about anything and thouch him with akwardness.