Falling for my friends GF. WTF do i do?

Wow, So heres the story. My gf left me about 2 months ago for another guy. i honestly didn't think i could ever want another woman again. i was wrong. It's been going on for a few weeks but I'm sure of it now. i'm falling hard for my buddies (roommates gf. Shes unbelievable. We just have so much chemistry and they have none. Bit they have been together for 4 years. they don't go out together. He's a bit of a dork and doesnt party much. Tonight we went downtown and he stayed home. i danced with his GF all night and she deemed me her "going out boyfriend". I could never put anyone, especially a friend through what I've been through with my gf. And honeslty I think she feels something for me but wouldnt do that to her bf. But we are just awesome together. This is just my luck though. Finally finding a girl after i lost the love of my life and she is taken by my good friend. Oh my. what do i do?