Cohabitation agreements (also known as nonmarital agreements) are similar to prenuptial agreements for couples who are planning to marry—but cohabitation agreements are for people who are living together and having a sexual relationship without being married. These agreements address issues that may arise during the relationship (payment of rent and other expenses, household chores)—and issues that may arise if the cohabitation relationship ends (ownership and division of home or other property, support).

In Colorado, cohabitation agreements, also known as nonmarital agreements, are recognized and enforceable. These agreements allow couples who live together but are not married to outline their financial arrangements, property rights, and responsibilities during and after their relationship. Colorado law does not provide the same automatic legal protections for cohabitating couples as it does for married couples, so a cohabitation agreement can be particularly important for ensuring that both parties' interests are protected. Such agreements typically cover the division of property and debts, financial support, and other relevant issues should the relationship end. It is advisable for each party to have their own attorney review the agreement to ensure that it is fair and complies with Colorado law. While Colorado does not have a specific statute governing cohabitation agreements, the courts generally uphold them as long as they are in writing, entered into voluntarily, and not unconscionable.