Fascinating. Even in a non-mainstream activity, I can't seem to be mainstream.
My wife is bored with most BDSM movies. Her inevitable question is "Where's the sex?" If there isn't some sort of sex going on -- lesbian, hetero, whatever -- the movie bores her. Now, I can get hot-and-bothered by non-sexual domination, but I, too, prefer to see something more "interactive" -- be it weird machines, girl-on-girl, or male-female coupling.
BDSM is an important part of our sex life; ropes and clamps and prods stimulate my wife's libido and prolong the sexual act for me. We often do role-playing -- cowboy and Indian wench (she's Apache, I'm white) , burglar and late-night office worker, and other scenarios that might seem a tad cutesy for some. It involves rope, pain, pushing my wife beyond her inhibitions -- such as when I took her in her office one late night, after everyone else had gone home. Very dangerous (job wise) -- but extremely fullfilling for both of us. And I can't imagine doing that without sex involved.
Don't think we're just playing games; there's some serious control going on here, as when I "attacked" my wife in her office. It was a matter of domination, of making her do something she did not want to do, but that in the end she thoroughly enjoyed.
Our marriage is based on trust, love, and lust (in that order). Perhaps we're not "serious" BDSM "players"; for us, it is less a lifestyle than it is a powerful spice that keeps sex exciting after twenty years and three kids.
Maybe my wife and I are the "kinky" ones here, since love and sex are most certainly at the heart of our BDSM activities.