Hey, I can still have all the reproductive success I can handle and yet have you over for dinner with enough left over for the week. It simply doesn't require enlightened self-interest to have sex or dine well.
Those humans who cooperate with each other and adhere to basic rules like, "Don't kill each other" "don't have sex with another's mate" and "Don't steal from each other" will, in the long term, leave more descendants than those who do not.
He stole everything and had sex with every woman within his view at anytime he wished.