You'd make a great psychologist, because intimate knowledge of others' motivations is intensely interesting to you. And when you get romantically involved with someone, the relationship is usually intense. You attract people who have secrets to protect, because they know that in you, they'll find a good and discreet listener, someone they can trust.
Your friends come to you to unburden themselves of whatever heavy feelings or situations they've been living with, and it's the same in your love life. Your lovers feel safe with you, because they know you'll protect their privacy. You create a feeling of intense, serious intimacy by making your sweetie comfortable enough to be vulnerable -- to bare all, so to speak. And you're not the type to shy away from difficult emotions. If anything, you're even more interested the odder things get, because you want to get at the base of human experience -- what it is to be a person here on earth, to live and love and feel with a human heart and mind. You want to know what it is that makes people tick, starting with your sweetie. You recognize that, the deeper you go into human motivation and experience, the closer you'll come to some universal truth.