Common Law Marriage
A common law marriage is where you and your spouse decide -- before you are married -- who gets what and how your assets, and/or children are shared (or not shared) should you and your spouse later decide to divorce. It involves a contract that you and your spouse both agree to beforehand, and does not require a State marriage license.
See also:
Family Law ... Marriage, and Divorce
5 Reasons why Christians should not obtain a State marriage license