My husband is a black belt in Karate and a yellow belt in Judo, but he is a white belt in Jiu-Jitsu. Therefore, it really annoys me that he taps me out most of the time when we roll. It's not because he uses his strength and size against me (well, sometimes he does), but mainly it's because he has a natural ability to go with the flow. While I am technically superior, he is light years ahead of me in the things that cannot be taught. He is very calm when he grapples, and he can feel things much better and faster than I can. We like to call his innate ability "Joe-Jitsu".
He thinks it's because he is comfortable in the chaos. To him there are no positions, there are only opportunities for submission. He always defeats me in the scramble, because he does things that I never expect. He doesn't react the same way someone with more training does. His natural understanding of body mechanics and how submissions work allows him to see them from almost anywhere, which is a skill that I do not yet possess.
As far as training for self-defense, I don't think I could find a better grappling partner than him. Most people on the street who would attack you probably don't train Jiu-Jitsu. They are not going to move and react the same way an experienced grappler would, you never know what they might do. So to have someone to train with who reacts more like an outsider, yet possesses a natural talent for body movement, is the best possible training scenario I can imagine.
Today is our 16th wedding anniversary, so as a gift to him I am going to post our open mat video where he makes me look like a fool. Enjoy it honey, because someday soon my Jiu-Jitsu will surpass your Joe-Jitsu, and when it does, I will pwn you!