Why emphasise on monogamy?

[CapnAwesome]

While people may want more then one partner, they normally (and contradictory) want their partners to sleep only with them. So that biology argument goes both ways. Monogamy on a macro level is what is best for society. Every polygamist (Men marrying more then one woman, not free love which is very different) culture has treated women like shit, every single one, from ancient polygamist societies to modern Muslims or Fundamentalist Mormons. These cultures also produce a huge excess of horny young men with no outlet, which destabilizes things for an obvious reason.