Am I stuck not dating?

I haven't had a girlfriend or "hookup" since 18. I'm 23 now, in great shape, steady job, am nice, have my own place, and take care of myself, but any girl I meets blows me off. All of my friends (girls included), don't see any logical reason why I continually fail. I was close to getting married with my last girl, but she cheated on me, and I called it off. The only theory I've heard is that I can't produce pheromones, is that possible?