|"Only dull people are brilliant at breakfast"
|"The liberal soul shall be made fat, and he that watereth, shall be watered also himself."
-- Proverbs 11:25
Abraham had two wives, Sarah and her handmaiden Hagar. King Solomon had 700 wives, plus 300 concubines and slaves. Jacob, the patriarch who gives Israel its name, had two wives and two concubines. In a humanist vein, Exodus 21:10 warns that when men take additional wives, they must still provide for their previous one. (Exodus 21:16 adds that if a man seduces a virgin and has sex with her, he has to marry her, too.)
But that’s not all. In biblical society, when you conquered another city, tribe, or nation, the victorious men would “win” their defeated foes’ wives as part of the spoils. It also commanded levirate marriage, the system wherein, if a man died, his younger brother would have to marry his widow and produce heirs with her who would be considered the older brother’s descendants. Now that’s traditional marriage!
Later Islamic and Jewish sources, unclear on these parameters (the prophet Muhammad, of course, had several wives), debated whether it is permissible for a man to marry a three- or four-year-old girl. St. Paul, meanwhile, said that marriage was a compromise between the ideal of celibacy and the unfortunate fact that people like to have sex. Fortunately, we pluralists can appreciate both those religious traditions which advise men to marry little girls and those which tell them not to marry anyone at all.
And of course, even until the present day, traditional marriage has meant arranged marriage. The notion that two adults would enter into a marriage on their own volition is a radical innovation in the institution of marriage, at most two hundred years old.
Oh, and let’s not forget that in Europe and North America, marriage was considered a commercial proposition first and foremost—not a romantic one. Princes married princesses not because of fairy tales, but because their parents had political alliances to consider. Further down the economic ladder, people married for a variety of biological, commercial, and genealogical reasons—but rarely for love. (See Stephanie Coontz’s excellent Marriage, a History for more.)
So, let’s see if I can total all this up. Traditional marriage is one man with multiple wives, multiple concubines, wives conquered in war and wives acquired in levirate marriage, possibly including girls under the age of ten, but definitely not including anyone of a different ethnic group, in an arranged marriage with disposition of property as its purpose. That seems very different from “one man, one woman,” does it not?