I am pretty sure that prior to these times it was natural for a man to take 1 wife and cling to her, support her and protect and care for their offspring together, it's just that in the Bible God blessed this practice and made it a covenant just like the covenant between God and Abraham.
Fair enough. I guess I was thinking of, say, hindu marriage rites which would have predated Christianity/judaism. Most cultures have similar rites which BTW adds to the argument that gay marriage is an oxymoron.