Florencia: "I've had it. We've been married for 24 years, 7 months, but we're not making 25. I'm filing for divorce."
Juan: "Fine. But guess what? We were never actually married."
Florencia: "What?! That's absurd."
Trial Court: "Yep, Juan's right. You were never actually married. Divorce petition dismissed."
Florencia: "Okay, then. New lawsuit. I was a putative spouse. Because I definitely thought I was married to you. So give me the same relief."
Juan: "I've got some Latin words for you. 'Res judicata'. You already lost. You can't sue me again."
Court of Appeal: "Not so fast. This is California. A 'nullity' action is a different primary right than a 'divorce' action. So the lawsuit can continue."
That's essentially the dialogue that underlies this opinion.