[gus_massa]

> Our culture is in middle of making unprecedented changes to a core social institution that goes back into prehistory.

The history of human’s relations is much more complicated, and it changed a lot even in the historic time. There is nothing new under the sun.

Monogamy: http://en.wikipedia.org/wiki/Monogamy

Poligyny: http://en.wikipedia.org/wiki/Polygyny

Polyandry: http://en.wikipedia.org/wiki/Polyandry

...

Homosexuality in Greece: http://en.wikipedia.org/wiki/Homosexuality_in_ancient_Greece

Homosexuality in Rome: http://en.wikipedia.org/wiki/Homosexuality_in_ancient_Rome

...

There are much more articles, but I don’t want to link to the whole Wikipedia.