I'm a 28-year-old guy in grad school. I love my girlfriend, but I don't want to have sex with her anymore. I'm hitting the books and writing papers day and night. She still wants to party -- go out and smoke pot and drink a lot -- which I used to enjoy but now find empty and stupid. I keep feeling seriously annoyed with her choices, and I'm increasingly attracted to other women. Is this the end, or should we try to make it work?

--College Boy

When you're slaving away in grad school, it can be hard to feel connected to somebody whose idea of higher education is Googling how to grow pot in your closet.

Your eye-rolling at your girlfriend's choices -- to the point where you could sprain a pupil -- is not exactly the stuff a peppy libido and a happy future together are made of. In fact, the mounting lack of respect you have for her is the starter emotion for contempt -- an ugly emotion that plays out as sneering disgust. Relationships researcher John Gottman finds that contempt leaching into a marriage is the single best predictor that a couple will split up.

Conversely, for a relationship -- marital or just committed sans paperwork -- to have staying power, you need to have the hots for your partner, not just as a sextivities provider but as a human being. This involves having deep admiration for what they think and value, which shapes who they are and how they go about life.

Did you start out in a place like that with your girlfriend? If so, you two should have a chat about where you are now and whether you can get back there. The answer may not be immediately apparent, so you might set a defined period of time to give this a look -- with a deadline to make a decision. Ultimately, there has to be enough that connects you to overcome the stuff that divides you, or the only thing that will ever be throbbing in your relationship is that big vein in your neck.