How do i get this sbag to leave me alone?

I asked this guy out on a date back in high school two years ago, and he turned me down, laughed and humiliated me saying he only dated popular girls. I was kind of geeky back then. Yesterday i just found out that he goes to the same college as me and i met him in the student hangout. He said that i looked hot and said he would like to go on that date i asked him to go on a couple years back. I told him to go to hell and that i had a real man.(I have a boyfriend)I told him that i am not going top leave my gentlemen boyfriend for a slime ball like you and walked off. He said he is going to keep pursuing me. I have not told my boyfriend about this yet but i really want that to leave me be.