What should I do about this jerk?

I like to think of myself as a mature person. I'm a junior in college, and I'm currently in the process of getting my Bachelor's in the Science of Nursing. I also have a problem of being too nice to people. I don't think I necessarily let people walk all over me, I just don't like to intentionally hurt others. Well, to get to my point, my boyfriend has a friend. We're all in our early 20's. Well this guy is always a JERK to me. He's not really rude enough to cause my boyfriend to say something, but he still gets under my skin. I don't really know how to explain it, but he's one of those people that TRY to make you feel stupid. He TRIES to make me feel dumb. And I used to just "play" along because in all reality, I'm much more intelligent than him. I'm just a little ditzy sometimes. I'm book-smart, but sometimes I lack common sense. And this guy takes full advantage of that. It's almost like he goes out of his way to "punk me out" or point out my mistakes/flaws. I get frustrated with myself sometimes because I know I'm intelligent and can easily reply with a comeback that will either hurt his feelings or make him feel like the moron, but my conscious tells me not to. It's like even though he's being a jerk to me, I still don't want to say something to hurt his feelings. Well there's a catch to this whole thing, apparently. My boyfriend and I have been together for five years, and that's how long I've known the other guy as well. The other guy (the jerk) tried to date me right before I got with my boyfriend and he's been "cynical" ever since in different ways. Before I started dating my boyfriend he was nice to me and never acted this way, but could he really hold a grudge for five years? Or is he just being a jerk to be one? My main question is, should I ignore him? Should I stop playing nice and make him feel like the moron that he constantly tries to make me feel like? Any other ideas?