Love friend's girlfriend...?

So, this is cliche, but bare with me.
For the past couple of months, I've been friends with a girl, but she has been with my friend for around 4-5 months. I see both people each day, and like the guy as a decently close friend, and believe myself to be in love with the girl. I know the girl and I are closer than most of her "guy" friends, but don't know how to handle the situation. Sometimes, it seems to me that I have a chance, other times, it seems like there is no way I would be able to go with her. I feel like I want to try to ask her out, but that would mean alienating myself from the boyfriend of the couple if she said yes or no.

Essentially, love triangle. I love good friend's girlfriend. I don't want to hurt anyone, what should I do?