Polygamy is largely a function of Ego of both men and women.

Women seek to acquire capital, status, and for their children to inherit the ego (mostly society's view of that ego) of the alpha male. Men seek to monopolize reproduction, as well as build a society that is secure to them, growing their ego's and power until they monopolize reproduction. Ego reaches it's peek when one believes they are omnipotent and omniscient, and spread that belief to the rest of society. Greek and Roman Gods are very much so an ego trip trying to continue itself. When times are good, we get war and harems. When times are bad, we get the downfall of society due to infighting. Very few individuals are happy with this arrangement, which is why it's been torn down so many times over the millennia. E.G. It's a common saying, the first generation builds the business, 2nd generation runs it, 3rd generation ruins it, and the history of empires tends to follow that trend. There's a reason we replaced Polytheism with monotheism, and that's so no one man could aspire to become a God. There's a reason why priests weren't supposed to marry and have children; clergy were the spiritual leadership of an ego driven society, trying to drive that society in a constructive direction.

Monogamy is the practice of making the maximum investment in offspring that is feasible. The closer the union between man and women, the more complete the children will be; if the couple unconditionally loves each other, the child will unconditionally love themselves which comes out as confidence later in life. They also make every investment they can in their children (instead of in a bigger ego; bigger house, luxury car, vacations, and so forth). This in turn forced women to marry men for their physical, moral, emotional, and intellectual traits which was an indication you'd be a good breadwinner but more importantly, that the resulting offspring would be good members of society.

What we've had in the last 60 years largely is a psychological war waged on the population in order to further the ego of the corporation or state. Ultimately, this is a self-defeating path; the ego of the corporation and state will ultimately monopolize reproduction but this prevents society from delivering to the state and corps what they need to survive. Ultimately, games of wage arbitrage have resulted in an economic system where the financial markets no longer represent actual production, and where investment in society has dwindled to the point we need to put in place unabated immigration, student loans, H1B's, and Outsourcing in order to continue propping up an already collapsed political system and economy.

Democracy was originally invented to control the egos of leadership; Trump being elected is simply the electorate hiring someone who is completely against the ruling class and will tear them down, and this is not the first time this has gone on, although the volume of bitching the ruling elites have done is quite epic. First he's going to do away with the subsidies; H1B's, Immigration, eventually Student loans. Then he's going to begin up large corps while simultaneously restoring the middle class's income who will in turn, form their own tribal governing bodies and lobbying bodies. That in turn will bring the corporations and state in check.

Women who chase ego never win, let them, ignore them, go find someone else. They will get what they deserve.