...the world for millenniums? Long before any Christian influence?
I think 'marriage' came to be, not because some guy wrote it in a book, but because people naturally want to stay together, and from this natural attraction evolved the desire to proclaim and celebrate commitment, which many cultures for thousands of years identify as 'marriage'.
I think this explains why marriages have existed long before the writing of genesis, and existed in cultures all over the world which did not have any christian influence.
How do you explain it?