Six days after the 9/11 attacks, I visited the northeastern Pennsylvania home of a Port Authority of New York and New Jersey police officer who was listed among the missing.

The grief-stricken woman who answered the door introduced herself as his wife. We sat in her kitchen, and she told me of her desperate hope that he had survived the collapse of the Twin Towers. She loaned me a photograph so that his picture could appear in the newspaper and told me about their son, who was in 10th grade.

It was later confirmed that the missing man had died in the World Trade Center, along with so many others. He had planned to retire the next year.

Compounding the tragedy for the grieving woman I had interviewed was the fact that she and her partner had not actually married, though they had built a house together and had a 15-year-old child. As a judge would later tell her, she may have considered herself the man's wife, but she was not.

Less than two weeks after 9/11, the police officer's adult daughter from an earlier relationship applied for a death certificate, naming herself and her half brother (the 15-year-old) as survivors, and herself executor of the estate.

The officer's companion sought unsuccessfully to prove in court that she was his common-law wife. When that effort failed, she and her son had to move so that the daughter could sell their house. The officer's substantial death benefits went to the daughter and the son.

It was a dramatic illustration of how being married, rather than living with someone as if married, can provide financial protection and security in the event of an unexpected tragedy. Money can't make the pain of losing a loved one go away, but it can ease financial stress, keep the house out of foreclosure and maybe put the kids through college.

Had the couple been married, the woman would have been entitled to a $130,000 federal payment for

uinformed government workers killed on duty, as well as widow's benefits from the Port Authority and the Army, as well as the house and Social Security survivor benefits.

While some of that financial support would not be available to a typical widow, Social Security survivor benefits are available to most spouses, with additional cash benefits for every child until they reach age 18. Even someone with a modest income could leave meaningful benefits to a surviving spouse and child through Social Security.

Absent a marriage certificate, a will also could have helped. The police officer didn't have one.

There are certainly reasons why people might live together before marrying, or instead of marrying, and I recently wrote that census data show the number of unmarried partners living together increased by nearly 63 percent from 2000 to 2010 in Berkeley, Charleston and Dorchester counties. Statewide, there were fewer married couples with children in 2010 than a decade earlier, while the ranks of single parents soared.

I won't touch the sociological issues involved, but I will point out that if you're living with someone, or have a child with someone, and you aren't married, your partner could suffer financially in ways you would not have wished if you unexpectedly die. That's particularly true if you don't have a will, which could at least guide the distribution of your assets and any death benefits.

Just look at what happened to some of the survivors of the Charleston Nine, the firefighters who died in the catastrophic 2007 Sofa Super Store fire. Different forms of compensation and charitable contributions amounted to well over $1 million for each firefighters' family.

Many of the firefighters did not leave a will, so it was left to a workers compensation judge to decide who was eligible for payments, and that came down to legal definitions of dependency. As a result, some firefighters' adult children, a firefighter's live-in girlfriend and another's mother were among those who received nothing.

"He wouldn't have wanted this," a deceased firefighter's sister said after one of the compensation hearings.

What would you want to happen? That's what a will is for, and if people depend on you, it's a good idea to have one.