So background here, we met around two and a half months ago on Tinder, and started a relationship a few weeks after that. We go to separate schools but live close enough that it's not a problem to see her whenever I want, and vice versa. 

Really, the relationship is going great. I like her, and while I obviously don't speak for her, it does seem that she likes me.

I guess to be complete, I'll include this: I was a virgin before I met her. She wasn't, and we've had sex a bunch since we started dating. The sex too is good, obviously for me and I think for her as well. 

The reason I want to break up with her is I just know that I'm not going to marry her. She's great, but I see this as a fun relationship that will at maximum end after college (a year and a half more for me). Also, she has a few personality traits that get on my nerves. I attribute this more to us being slightly incompatible (or me being a jerk) rather than her being annoying, but the effect on me is the same. 

I want to clarify that I did genuinely get into this relationship for the right reasons (I liked her, love of my life and all that), but now that I see this isn't going to a permanent thing I feel inclined to cut my losses and move on. 

I don't want to break up with her without having a genuine reason why, as I still very much enjoy being with her. I'm just afraid that I'm going to sink so much time into her that I won't want to end it. 

On the other hand, if I don't break up with her, am I just using her for intimacy when we could both be looking for more compatible partners?