I have a mild history of SI, but I am engaged in BDSM play these days.

For me, the SI was about feeling strong and in-control, so I say that I've "outsourced" that need to be validated in that way to someone whom I can trust to have my best interest at heart and to stop if he thinks I want more than I should take. I don't have an incredibly high pain threshold, so he doesn't need to worry about that.

This isn't about sexual gratification for me either-- I get little to no direct sexual thrill from the pain play. I do feel very good about myself afterwards though; relaxed and in-tune. If I can take a lot that day, then I can usually reach an endorphin high that's sort of like a blissful meditative state, and those are worth more than all the orgasms in the world!

Anyways, I don't think you're alone at all. Hope this helped.