Ask the Expert: Protection for unmarrieds

No. New York doesn't recognize common-law marriage. The law entitles married people to inherit one-third of each other's assets — no matter what their wills say — unless they waive that right in a prenuptial or postnuptial agreement. But it doesn't give unmarried couples any rights based on their relationship.

If you plan to live with someone to whom you aren't married, you should have a written agreement about your respective financial obligations. If you stay together for the rest of your lives, this piece of paper protects the survivor. If you break up, it protects you both.

In a committed relationship, you'll want to sign health care proxies and durable powers-of-attorney — documents that give your partner the legal right to make your medical and financial decisions if you're incapacitated.

To protect each other after death, write wills in each other's favor, name each other as life insurance beneficiaries and keep assets in joint names with right of survivorship. (If you want to leave your respective shares of the house to your children by a previous relationship, you can give each other a lifetime right to live there.)

Even if you're just roommates, a written record of household expenses can prevent quarrels about whether you're both contributing a fair share — and if you both own the house, a record of who contributed what to its purchase and to the mortgage, taxes and capital improvements is indispensable when you sell it.