Simple Answers
Even though this thread has already been replied to so many times that it is virtually a joke, I may as well try to test out some of my conclusions here to see if they work.
Why do men pay for sex?
CULTURE - America was founded by religious fanatics of the worst kind: Christians. Because of that, their concepts of morality and immorality, ESPECIALLY pertaining to sex, have always been with us. Overseas its a different story, but in the US, women are still perceived in many ways as the sinful gender because they incite sexual appeal (more often than men at least) even if they don't intend to. Also, since Christianity is a patriarchal religion, the usual bullshit about men becoming "MEN" by means of physical dares and sexual conquest still exists...which makes life a lot harder for women who are conditioned on an almost subconscious level to abstain from sex to remain "pure". So because women are conditioned to refrain from sexual escapades, it makes it harder for men to get sessions with them unless they go through the whole "dating ritual" and begin the pretense of a relationship, which is the only way our society allows people to have sex.
VARIETY - Women are almost always looking for a lifemate. I don;t know if this is the way they feel or if it's how they have been TAUGHT to feel, but whatever it is, women just refuse to have sex (many times) unless it is a monogomous relationship. Not good for men who want to taste different kinds of women. That is probably why porn is such a profitable business: it allows men to mentally have sex with hundreds of different women...which a g/f or wife would NEVER approve of.
OPPORTUNITY - Chris Rock said it best:
"It's EASY for women to turn down sex! A woman gets offered dick at least THREE TIMES EVERYDAY! Any time a guy is nice to you or says something nice, he's always saying 'how 'bout some dick?' in between the lines."
Any woman in America will tell you this is true. But here's the most accurate part:
"MEN DON'T GET OFFERED SHIT!"
I've been running an experiment of mine since I heard this sketch on HBO. Ever since then, I have never tried to seriously get with a girl. I've been nice, yes, occasionally flirty, but NEVER have I ever seriously tried to hook up with a woman. And you know what? Not a single woman I know has ever offered sex. Chris Rock was right. If men never tried to get laid, they never would.
The truth is, women like sex as much as guys do. The problem is the motives are always different: guys want sex for fun, women want sex in context. Now, there are women out there who do want sex for fun...the problem is that in AMERICAN culture, these women are usually unsanitary or unbalanced: it seems the cultural authorities make sure that sane, intelligent women are turned off of casual sex, so the only other option is the freak show.
The worst part about women who are into casual sex is that they meet the MEN who are into casual sex. And I honestly believe that any guy who dislikes a promiscuous woman is never really mad at the woman, he's mad at the other guys she has slept with. Because there is one thing that men know more than anyone and that is just how purely, absolutely fucking NASTY other men can be, especially the ones with sex on the brain 24/7. Women with venereal diseases often don't know they have them, so I can;t say that they are to blame entirely.
So men pay for sex because it can get them a simple thing that is in demand without signing a long-term contract for it. This doesn't make it a good thing, but it is simple enough.
And as for all the safety bullshit about STDs and why casual sex is bad, I might point out that the sex isn't what kills us...its the disease that it transmits. The disease is our enemy...not the act.