I've been telling stories since before I could write, and practicing BDSM since I built a Meccano rack to torture my sister's Barbie*, so it seemed natural to combine the two. But for many years that meant writing for the very limited porn market, which didn't want literary quality, just lists of flogging and fucking scenes. I wrote Impudent Crimes in 1985 trying to bridge the gap, and fell into it: mainstream publishers said the book was pornography, porn publishers said it didn't have enough hot stuff.
Forward 25 years to digital publishing and a niche for every genre, and the nice women at XCite Books told me that what I was writing was BDSM romance. I claimed the term with delight. I think that's just what I've always been writing (or trying to write, I still have more to learn about characterisation and inner motives.) Even when I write grossly non-consensual stories, my characters keep on falling in love. Maybe I'm just an old softie... with a whip.
I chained my second girlfriend to the bed and never went back to vanilla. In the course of a long interesting life I've lived in a bisexual foursome marriage, owned collared slaves both female and male, made fetters and dungeon furniture for a business, had more submissives than I can recall, and occasionally been on the other end of the chain. These days my wife helps me to get the sub's viewpoint right.
(*And don't tell me that's not consensual, Barbie spreads her legs every time she bends over, that's a pain-slut if I ever saw one.)