One study has shown that men who live in polygamous cultures live 12% longer, on average, than men who live in cultures that enforce monogamous marriage. Researchers are unsure why this is true, but many suspect that having many children with more than one wife contributes to the longevity of these men. The study compared the lifespans of men who were more than 60 years old and lived in countries that practiced polygamy to those who lived in nations that did not allow polygamy.
More about polygamy:
The term “polygamy” refers to multiple marriages. Many polygamous marriages and cultures are more accurately called “polygynous,” a term that means “involving many women.” These marriages are characterized by one husband who is married to multiple wives.
Islam permits men to have as many as four wives, and the men are instructed to treat each wife “fairly.”
Some Nazi officials pushed for the legalization of polygamy as a way to potentially reward war heroes and provide for women who might have had fewer options for marrying after a war, given that so many men would be either dead or seriously wounded.