In the United States, palimony is a court-ordered financial settlement between two former lovers that, though never married, cohabitated for a significant period of time. While similar to alimony in principle, there are distinct differences between alimony and palimony. The desire to cohabitate without marrying has been a growing trend since the 1960s. Many people feel their relationship "does not need a piece of paper" to be validated. Others choose to cohabitate to see if the relationship can work before taking the plunge into marriage; and same-gender couples cannot legally marry at all.

For some, the institute of marriage is seen as a legal entanglement — an unnecessary complication of red tape and intertwined assets that only need to be untangled when the relationship ends. With a marriage-failure rate close to 50%, many people who have already gone through an expensive divorce swear off marriage. However, avoiding marriage doesn't preclude one from legal problems. Unfortunately, relationships that start out more than amicable can end up less than civil, and misunderstandings about cohabitation that were never talked about, agreed upon, or clearly understood by both parties can lead to a palimony suit. A palimony suit asserts that one partner is owed a financial settlement from the other partner.

Though laws differ in each state, presented here are some general key factors that might play into the court's decision to award or deny a palimony settlement:

• Longevity of the relationship.
• An implied understanding between partners that one would financially provide for the other for the rest of his or her life.
• Spoken promises between partners that can be substantiated or corroborated.
• Written financial agreements, if any exist.
• Ability for the plaintiff to support himself or herself.
• Sacrifices made by one partner to support the other by way of giving up a career path to take care of the home or children.
• Sacrifices made by one partner to put the other partner through school so that he or she could earn a professional degree.
• Disparity between incomes.

Unlike alimony, palimony settlements usually involve a lump sum paid at once, versus permanent monthly payments. A further difference is that palimony does not divide "common assets." In a palimony suit, the legal owner of any assets gets those assets without question, even if the partner has paid into them and considers them common property.

In 1982, Scott Thorson brought the first publicized palimony suit against entertainer Liberace (1919-1987) after a cohabitation of five years. Thorson asked for US$113 million and was awarded $95,000 in the settlement. The next famous palimony suit came in 1991, filed by Judy Nelson. Nelson sued tennis champion Martina Navratilova for palimony, concluding an eight-year relationship that ended poorly. Terms of the settlement were not disclosed.

In order to avoid being on either end of a palimony suit, some legal experts recommend couples take precautions. A cohabitation agreement is a good start. This agreement should cover expectations and arrangements so that in the eventuality of a breakup, both parties are protected. While an informal handwritten draft signed by both parties is better than no document, some legal experts suggest each partner retain a lawyer and allow the lawyers to hammer out the cohabitation agreement. This serves to protect both parties because it cannot be claimed later that the best interests of each were not properly protected.

Other advice includes putting both partners' names on common property and assets so that they can be divided fairly, or even inherited. This is particularly important in same-gender relationships in which couples might cohabitate for a lifetime, as common law marriage is not applicable. If the home, for example, is in the name of a partner that dies, the house automatically gets awarded to the relatives of the deceased, even if the surviving partner spent a lifetime helping to pay for it.

While marriage may be undesirable or even unavailable to some, it does provide many automatic legal protections. Before considering cohabitation, it is best to seek legal advice from a professional lawyer versed in family law in your state. This should help to ensure protection from potential palimony entanglements.