You don't 'always' attract douchebags - you have said so yourself that you have attracted men who appear to be, in your opinion, eligible.
I think a lot of people just expect Mr or Miss Right to fall in their lap instantaneously. A boyfriend is special, and if we met 'special' people all the time they'd not actually be that special, would they? The fact is, we generally find a lot of people physically attractive, but only a small percentage of that pool of people will we deem relationship material. You can't expect every guy you meet to want to be in a relationship with you. If there have been several guys since the start of university who you have seen as relationship material then perhaps you need to be more discerning and learn not to get your hopes up so easily. Is it that you're so intent on finding a boyfriend that you're pinning your hopes on guys you're actually not that interested in, and when they reject you you're more hurt about the rejection itself than the guy in question?
Also, why is it that you're calling these guys 'douchebags'? What have they done to you? Even if these guys have behaved badly, don't think you're alone in being on the receiving end of it. Everyone has bad experiences. Most people date and sleep around a fair bit before they settle into a relationship. When things don't work out with a guy, some people are very quick to throw insults. If you give us some examples of things that have happened then maybe we can help and see your situation more clearly.
Please don't fall into the trap of thinking that men fall into two camps: those who want relationships, and those who don't. When a 'player' meets the right woman he will drop his rakish ways and commit to her. If a guy won't commit it's because he's just not that into you.