I kind of relate. I'm not into sex and prefer to avoid it if I can, but if there was one person it was best with, it was my previous ex. Sometimes when I do things by myself, I still see her face and eyes in my mind, and the way she would look at me when she wanted me. There were times I really missed having sex with her. Not because of the sex itself, but because of the way I could actually achieve psychological/intellectual arousal with her. It was the way she could make me yield to her everything that I was. For me, that was the greatest turn-on ever.

If all of that makes sense. Might be something totally different that you're talking about.