How do you best avoid a person trying to ruin your relationship?

=(The Anti-Troll)= asked:


So I am an Asian guy dating an Asian girl, unfortunately we go to an overwhelmingly White college (both of us transferring out soon). I like White people but our college has few minorities in it and usually it is common to hear some racial slurs being thrown your way.

So there was this guy who was trying to go with the girl I currently date and she turned him down. Now I fall in love with this girl (we have been together for 7 months) and we are still going strong but this guy keeps trying to screw us up. He would jump inbetween our conversations, go around preaching about “multiculturalism” and how my girlfriend is close minded for sticking with her own race, he messages my girlfriend on instant messenger and she had to block him, he keeps trying to get near her and one time she even yelled at him for it, and last but not least he talks a lot of trash to me and tries to find reasons to fight me and verbally insult me in public.

What can we do here to avoid him for a couple more months?