Toxic Relationships

So I am 21 years old and in college. I live with two other guys I have known for a few years. They both seemed fine when I first met them which lead us to moving in together. Well one of them I have gotten to know pretty well and we have a good friendship thing going on. We have our differences, but we are both pretty understanding. No problem with this guy. The other one however....well, since moving in I have found out he is kind of an ass. Very insecure about himself, judges the fuck out of everyone, and a host of other really annoying phobias/personality traits. It has gotten the point when I can't stand being around him, and the thought of so much as helping him makes my blood boil. Which is awful of me to think that and I hate that someone has gotten me to think that. I am also not trying to say I am perfect either, I have my own flaws and quirks but I try to own up and fix them as best I can. My problem is I don't know how to keep living with him and be happy, because even though everything else in myself is all fine and dandy, one conversation with him ruins my day. How do I live with him and myself and make both of us happy, or at least myself. Honestly any help at this point would be greatly appreciated.

P.S. I haven't even told my girlfriend yet because I have seen what the reddit community is and I have a lot of faith in it.