Marriage goes way beyond the Jewish and Christian spheres. It's a far-reaching anthropological value. Strictly speaking it's a natural state, which means it isn't an invention. What we're missing most of all in contemporary times is an appreciation and acceptance of our contingency as beings. For want of this restful appreciation of what we really are, we have a tendency to become angst-ridden, semi-nihilistic types trying to find our bearings through acts of will and experiencing misery because we can never get there from here by traveling that path.