Ill give you a bit of advice.
insulting him will not make him leave you alone.
If he likes you than he will just turn on the charm evan more.
But theres hope, the piece of ammo you do have is your belayer.
Juat tell the jack ass bothering you to leave you and your " BOY FRIEND" alone. very few guys will continue to bother you. its not cosher to hit on another mans's girl, it is an unwriten rule about that.