it may suck, but you have to get over it (or at least pretend to... if you try any sabotaging make sure no one can tell)
What you should do is talk to your friend about your feelings towards this girl.If that doesn't work, well stop being his friend.
"Who's your best friend?"
if they are your best friend they should understand
I'd choose the girl.
if they where hot then hell yes! If you were going steady with this girl, a best friend would not interfere. However, you must also understand that is this girl does not feel the same way about you, you should not interfere with others approaching her, even a best friend. That would not be fair to your friend. I know it hurts, but it will pass.
If he was a good best friend he would stop going for this girl.
explain your mistake to your bestfriend, and let them know you're truthfully sorry about going out with the girl.
Two words. Jerry Springer.
Try to make your friend look bad.
If you do not like him then yes, you should.
honestly, i wuld tell my girl best friend whats going on and try to stay away from the boy cuz either ur going to break ur friendship with the girl for the boy.
Talk to him about it. Talk to the girl about it.