(what is the female sex drive)
It's an instinctive need to acquire the highest quality seed possible while ensuring the survival of the offspring. Anything that she instinctively sees as signs of quality seed will be seen as attractive. Dual mating strategy and betabuxxing comes in when the quality male doesn't want to take care of the offspring. Today, it only comes down to looking good because provider males became unnecessary and people have sex for gratification, not reproduction.