Sadly, polygamy simple is not congruent with human biology.
Using existing sexual practices, the probability of a males off spring is about 55%. The probability of a female is 45%. But the time the new born reaches adulthood, especially in second or third world countries, the sex ratio gets much closer to 50 50. Which implies a monogamous marriage as best fitting human reproduction.
But wait, as modern medical advances allow parents to select the sex of the child, by aborting females and carrying males to full term, I can only predict social instability for those societies. And for the few surviving females, it may become socially necessary for the females to take on two or more husbands.
Of course as a die hard male chauvinistic pig, I know bigamy is illegal, so surely 3 or more wives should be legal. Of course every time I get such ideas, my wife bops me over the head with a rolling pin. So please don't tell me wife I just posted this. What she does know won't hurt me.