Without a Will or Living trust, unless you have a legally recognized common law marriage (heterosexual couples only), a registered domestic partnership, a civil union, or a valid living together contract, your relatives will inherit everything.

Common Law Marriage

The belief that living together for seven years constitutes a common law marriage is a myth. Fifteen states and Washington, D.C., recognize common-law marriages only among different-sex couples, but you must "hold yourself out to be married" by, for example, using the same last name, referring to each other as husband and wife, and filing joint income tax returns.

The following states recognize common law marriage:
Alabama
Colorado
Georgia (if created before 1/1/97)
Idaho (if created before 1/1/96)
Iowa
Kansas
Montana
New Hampshire (for inheritance purposes only)
Ohio (if created before 10/10/91)
Oklahoma (only if created before 11/1/98. Oklahoma's laws and court decisions differ about whether common law marriages formed in that state after 11/1/98 will be recognized.)
Pennsylvania (if created before 1/1/05)
Rhode Island
South Carolina
Texas
Utah
Washington, D.C.

In general, common law marriage recognizes you as a legally married couple in every way, even though you never obtained a marriage license. If you choose to end your relationship, you must get a divorce, even though you never had a formal marriage. If you have a valid common law marriage, your common law spouse will inherit your property as if you were a married couple.

Registered Domestic Partnerships and Civil Unions

In California, Oregon and Washington, same-sex couples or heterosexual couples over the age of 62 may register with the state as domestic partners. Civil Unions for same-sex couples are legal in Connecticut, Vermont, New Jersey and New Hampshire. Massachusetts is the only state that allows same-sex couples to marry. Rights of domestic partners or members of civil unions vary from state to state, so you should speak to an estate attorney when planning your estate. In New Jersey, for example, partners in a civil union have all the same rights as if they were married, and for the purposes of inheritance. California considers that domestic partners have the same rights as married couples. An attorney in your state can advise you about specific rights with regard to inheritance.

Living Together Contract

A living together contract is a written agreement between the parties of an unmarried couple, gay or straight, with regard to ownership of property and other possessions. Since a living together contract is recognized in most states, it may ensure one party’s property is left to the other or according to whatever arrangement the couple makes. It does not take the place of a Will and will not go through probate.

Other Ways to Ensure Your Partner Inherits Your Property

Although unmarried couples do not receive federal protection like married couples, documents can be developed to provide some of those protections. The laws of each sate identify the rights of married couples and blood relatives. If you are in a committed relationship but not legally married, you need to take certain steps to protect your partner. Otherwise, blood relatives, such as parents, children and siblings, may have rights to exclude your partner from inheriting your property.

If you want your partner to inherit your assets, you should consider these steps:

• Writing a Will naming your partner as an heir to whatever property you would like him or her to have.
• Naming your partner as beneficiary on all retirement accounts and life insurance policies that you want to pass to him or her. Remember to change the beneficiary designation documents, including those you had in place before the relationship began.
• Structuring ownership so that property passes to your partner. "Joint tenants with right of survivorship" will accomplish this goal.
• Establishing a trust to pass property to your partner in a tax-efficient way. Spouses can transfer assets to each other tax-free, but unmarried partners cannot, so consult a tax adviser or estate planner to help you make the most tax-efficient choices.

Even with some of these protections in place, you should write a Will. In a Will, you can leave property you don’t think of or don’t yet own, such as a house you inherit later on from your uncle. Any property not specifically bequeathed goes into the “residuary” which covers all property not left to a certain person. You can name your partner as the residual beneficiary so he or she gets that property. A Will also allows you to nominate a personal guardian for any minor children, and to name an executor to control the property distribution and handle the administrative and court duties.