04/18/2012 09:44 am ET Updated Jun 18, 2012

Living Together Is Different When You're Older

When I was 18, I moved in with my first love. This was the late 1960s and as much as I loved him and he loved me, we both knew that we were too young to get married. We both had college degrees to pursue, wars to stop, injustices to rectify and a world to change. Back then, living together served many purposes, not the least of which was to seriously piss off our parents -- a good thing.

The arguments with my parents -- both sets of parents actually -- over the issues involved with cohabitation were about as ferocious as they come. My parents warned me against it in sometimes crude terms -- "he won't pay for what he gets for free" -- an oblique reference that living together eliminated David's need to marry me since he was getting laid while staying rogue. His parents questioned my very character. "Nice girls wait until they see a ring," I was told.

We, in turn, accused them of preferring a 1968 version of "don't ask, don't tell," where they didn't really care what we did just as long as their relatives and friends didn't find out about it. We also spoke of the infidelities in our own parents' unions, the hypocrisy of them telling us about the sanctity of marriage.

Things today are much simpler, I suspect. According to New York Times' opinion piece, the majority of young adults in their 20s will live with a romantic partner at least once and some 7.5 million young couples are already shacking up.

Most young couples slip into living together without much fanfare. They date, start spending nights together more frequently and then someone's lease is up and the economic conclusion is reached that two can live more cheaply as one. There may not even be a conversation about cohabitation being a pathway to marriage -- although the Pew Research organization says almost 64 percent of cohabiters see it as such -- and I suspect almost no one's mother is saying she isn't nice for merging potted plants with the guy she's been dating for a year.

What's interesting though is that the recent conversation about cohabitation has been limited to it being a rite of passage for those in their 20s. The fact is, boomers are doing it too, just for different reasons -- and those reasons are about as far away from a path to marriage as they can get. Quite the opposite, actually.

Post 50s cohabitate because marriage in your 50s or 60s can be a financially complicated nightmare. You both come to this relationship with decades of baggage in the form of children, houses, stock portfolios and accumulated wealth. That's the best-case scenario. The worst-case scenario is when the two partners have uneven amounts of baggage: One has invested wisely and saved, the other pretty much doesn't have two nickels to rub together. One has kids who get first dibs and the other has a cat. One still works, the other doesn't.

In the interest of keeping things simple, they simply move in together, in whichever house is nicer, and come up with a formula for sharing expenses. Why get married, which will only complicate things?

There are just a few reasons for tying the knot once you pass child-bearing ages: Taxes and health being chief among them.

Take the case of a long-divorced stockbroker friend who had lived for almost a decade with a divorced doctor. The doctor has adult children from a previous marriage, the stockbroker does not. Together, they bought a home, took lavish vacations, dined out frequently and enjoyed the life they built together under one roof and without the benefits of a legal marriage. Until the day he was diagnosed with cancer. His treatment plan would be delivered out of state and never mind that she would miss work to take care of him -- many hospitals wouldn't even let a non-relative into the recovery room. And then there were all the complications with his estate and adult children; where would my friend wind up financially after caring for her beloved?

His diagnosis came on a Tuesday and they were before a justice of the peace within 10 days. Because sometimes, marriage serves a higher purpose.