Numerous religions allow or have allowed polygamy, basically giving in to biology. Polygamy is one man with several wives. Never the opposite.
Polygamy is a coherent evolutionary outcome. If you made a simple program to organize behavior:
- Males should try to procreate as much and as widely as possible
- Females should pick the « best » male to be the genitor of her children
We can understand the male urge from current stereotypes. The females would rather have part of the attention of the « best » genitor for their children than accept second best. One tenth of a rich sheik provides more than 100% of a (sexy) poor beggar.
Polygamy is poison to civilization. Even in the animal kingdom, for one lion king with twenty wives, there are nineteen frustrated males roaming the savanna. Do you really want to bump into them on a dark night? In a polygamous society, there is an important portion of men who have absolutely no chance of a relationship with a women (mating). This can drive to desperation and destructive tendencies such as suicide bombing. What do they have to lose?
But there is this little thing called civilization. Equal rights for women and all that. With more women working, they are less dependent on men and are less prone to accepting the lousy deal of polygamy.