monogamy
I think the easiest proof against monogamy is the persistant existence of brothels - even in countries where there is a strong religious taboo against such practices.
I did have a short history of the behaviour of Popes but it tried to pass off various activities as a joke, which I thought unecessary, so I can't quote a book reference but a quick web search for married Popes give (amongst others):
http://www.rentapriest.com/married_popes.htm
Within European peasant societies, it was acceptable for the landowner to have sexual intercourse with women on their land, married or not (some research on the 18th Century in England seems to point to the need for a woman to prove her fertility prior to marriage).
Foucault covers this in his easily readable 'History of Sexuality' vol 1 and also 'I Pierre Reviere, having murdered my mother and sister...' Foucault's argument seems to be that monogamy and control of sexuality was a specific response to social and economic conditions which grew up out of the post Enlightenment period and had a great deal to do with the nascent biological sciences and concepts of geaneology as well as an attempt to control populations within the urban (as opposed to rural) setting (this deals with the myth of particular social groups practicing monogamy, rather than the fact, which was that there was an attempt to force monogamy upon them).
A recent US study on intercouse with slaves showed a large number of white slaveowning men engaging in extramarital sex but not of black slaves with white women (DNA burries a myth). The conclusion drawn from this would agree with Foucault, that sexual activity within the European context is closely related to economic and political power and control.
There are cases in Africa of monogamist groups engaging in extra marital sex during specific days/ nights and this is not counted (by them) as sex, they are sitll monogamous.
With continued the growth of STD's amongts the under 30's, I would argue that monogamy was a socio political construct with limited affectiveness. Indeed, that STD's exist and can be very dangerous and yet still spread argues strongly against monogamy ever being a norm, as it would have died out if the practice could be confined to a specific group.
Regards
Martin Hogan