bro ...i think proper communication solves most issues..............be very frank about your feelings to your friend.....he should understand....................and you havent made clear that who does the girl loves or is she still neutral at this point? well if she is.... than its not too late to tell your friend to back off........it is unfair for your friend  that you have a secret anger against  him.......maybe if he findsout he will back off but if he doesnt.......THE compettition is on...........he knows it , you know it.....and now it depends who catches the girls attention first.............GOOD LUCK...