SANTA ANA, Calif. (AP) Same-sex partners who believe they are registered as domestic partners but are not have the same rights as people whose relationships are registered under the state partnership law an appeals court has ruled.

The decision reverses an Orange County court ruling that said partnerships are only legally valid if registered with the state.

The appeals court ruling allows Darrin Ellis, 35, to seek an equitable share of the assets from his relationship with former partner David Arriaga, 44.

Ellis and Arriaga were in a committed relationship for more than five years. On August 14, 2003, the pair met with their attorney to execute estate planning documents and their Declaration of Domestic Partnership. Arriaga was to send the notarized form to the California Secretary of State’s office, and Ellis believed Arriaga had done so.

It was not until the relationship ended in 2006 that Arriaga informed Ellis he had never mailed the Declaration of Domestic Partnership to the Secretary of State.

Ellis filed a petition for Dissolution of Domestic Partnership (the equivalent to a divorce) on September 8, 2006.

On October 24, 2006 Arriaga asked the court to dismiss the petition, arguing that no domestic partnership had been created because he never sent the notarized form to the Secretary of State.

The trial court agreed with Arriaga’s interpretation of California’s domestic partnership law and dismissed the case on February 2, 2007. Lambda Legal appealed on behalf of Ellis.

People in different-sex relationships who believed they were married and have lived their life as married only to find out later that their marriage was not valid are protected by California’s “putative spouse doctrine.”

Lambda Legal argued that California’s domestic partner law should give same-sex couples the same protection under the “putative spouse doctrine.” The trial court’s interpretation of the domestic partnership law raises serious constitutional questions, the brief argued.

In its ruling as panel of the 4th District Court of Appeals said there is “no sound reason” to deprive people of their rights if they “reasonably believed” they had registered as domestic partners.

About 49,000 couples are registered as domestic partners in California.

“This case shows how important marriage equality is to protect same-sex couples’ families,” said Lambda Legal Staff Attorney Tara Borelli, who argued before the court.