Marriage vs. Cohabitation

I'm disturbed by the common cultural acceptance of couples living together. Dennis Prager has a nice column arguing for the benefits of marriage from a secular perspective.

But just look at the words themselves for some insight.

Marriage comes to English from old French, most likely, and is always associated with joining, connecting, one-ness, and identified relationship.

Cohabitation means "being in the same space." You can cohabitate with dogs, ants, fleas, prisoners, or your weird brother-in-law Fred. There is nothing in the word meaning that implies a relationship at all!