So far most of our discussion has centered around two individuals, a male and a female. But individuals are really just a small part of a much larger system - the sexonomy. In the sexonomy, all males compete amongst each other to get scarce sex. All females compete with each other to get the best price from the men who demand sex.
Market demand is the total combined demand for sex of all individual men. Market supply is the total combined supply of all women. Equilibrium market price, the point at which market supply and demand overlap, is the general going price for sex.
The general going price is not a financial number, but a vague socially accepted standard for what a guy is supposed to give and a girl supposed to ask for. For instance, three dates before having sex might be considered the going price for sex. This would require the man to give up seven hours of time, perhaps $75, and maybe a few compliments.
What happens when people deviate from equilibrium? These cases will be considered next.