Actually Mary, I've been a highly respected member of several D&s, and other sexual, circles for over 20 years, I know hundreds of people involved, personally, and thousands via online foraa. I've been both a Dom, a sub, a student of sexual arts and massage, explorer of fetishes, but above all this, a passionate lover of consent.
I put your point of biological makeup being the reason men paid sex workers to one online forum subset. You've provided the laughter for the rest of the week, so thank you.
Saying a woman's hormonal procreational urges is akin to a man's "urges" to fuck is a direct insult to women. Men have no hormonal need to fuck. Some men have a need to exert control over women sexually, most easily found by paying a sex worker. Do you know in parts of Merseyside, tmi warning, a man can secure a deepthroat blowjob including semen swallowing for a tenner? But wait, it's their "biological makeup" 
.
Quite humorous you have little knowledge of the intricacies of D/s yet comment a man paying a Dom for sex won't feel exploited (the Dom). Given the man, the male sub, paying for the experience retains power and control over the entire situation, I guarantee you they do. That there is no actual D/s taking place.
Oh, I get it! You've been watching/reading Fifty Shades of Shite?
True D/s is a beautiful thing, subspace incredible. True D/s cannot occur when money (and consent removal ) is involved in such, as it involves the sub completely giving themselves physically, emotionally, spiritually to the Dom. A man paying a Dom is giving nothing of themselves in this way and caring only about their dicks.