A recent article from Psychology Today talks about human nature, sex, and the best theories on why we act like we do. From the article:
Women often say no to men. Men have had to conquer foreign lands, win battles and wars, compose symphonies, author books, write sonnets, paint cathedral ceilings, make scientific discoveries, play in rock bands, and write new computer software in order to impress women so that they will agree to have sex with them. Men have built (and destroyed) civilization in order to impress women, so that they might say yes.
Now go read it.