Some interesting thoughts on cohabitation from a new secular book called Twentysomething: Why Do Young Adults Seem Stuck?” (Hudson Street) by mother and daughter Robin Marantz Henig and Samantha Henig:
"You spend enough nights together that, actually, now
that you think about it, doesn’t it seem silly that you’re paying two
rents and constantly leaving the shoes you need at the wrong apartment? .
. . Living together has its hardships, but it’s also sort of fun, like
playing house. You experiment with cooking braised short-ribs and bicker
about throw pillows, just the way you always imagined you would one
day. The things that concern you about the relationship are still there,
but however hard it would have been to break up before, now there’s the
shared couch to consider, and the fact that you could never afford such
a big living room on your own. (And yes, this “you” here applies to
“me,” the veteran of two live-in relationships that ended in breakups
and couch custody battles.) Pretty soon you start to look like a married
couple anyway, so maybe it makes sense just to make it official.
Suddenly you have a wedding website and you’ve posted a poll asking if
the honeymoon should be in Europe or Jamaica, without ever fully facing
the very real question of whether you actually want to spend the rest of
your life with this person".