Haha..Resha? A best friend? Phuck her..oh u already did. It does not matter if u let ur GF know about this or not, all of u are in loss-loss-loss situation ( If it is serious relation). People who can't control themselves deserve a mess. My suggestion, next time when Resha comes, try threesome. Just relax and enjoy it man. U guys don't care about serious relationship anyway.