As these representative examples clearly show, many qualities typically considered essential components of marriage in the contemporary western usage are anything but universal: sexual exclusivity, property exchange, paternal responsibility, the intention to stay together through thick (much less thin), even that the two partners are of different biological sexes — none of these are expected in many of the relationships considered to be marriage in cultures around the world.
And let’s not forget that the history of *all* “religions of the book” includes religiously-sanctioned polgyny.