She loved being spread eagle on the bed, bound, and then taken.

Studies in the U.S. have shown that about a half of all men and women find the idea of bondage to be erotic. As with any study of sexual thoughts and behavior, the available studies are not well controlled and the best studies are now out of date.

A study in 1983 reported that 11% of men and 17% of women reported trying bondage. Decades have passed, and since Mapelthorpe and Madonna, SM has become far more mainstream. Handcuffs at adult stores are as much "novelties" as "kink."

There's no doubt that the total number of married couples enjoying the occasional bondage session is much higher.

They just can't fill out surveys, because you could say, "there're all tied up."