There is no common law marriage in CA. If she retains any attorney, there is a term called putative spouse that can be argued, which essentially is where man and woman are living as though they are married, cominling of funds, buying property together, putting themselves out to the public as if they are married, etc. There can also be some contract theories that can be argued. You might want to seriously think of consulting with a local family law attorney in your area.
CA has no common law marriages, no matter how long a couple is together, but it does recognize "Marvin" claims. That's a kind of contract claim named after actor Lee Marvin, whose live-in sort of wife sued because she had given up her own acting career to act as Marvin's hostess, etc., and she claimed that they had agreed that he'd treat her like a wife for property/support purposes, since he held her out to others as his wife. The court ended up not finding for her, but did rule that 2 consenting adults who have a relationship not based solely on sex can make an agreement, like any other adults, to share property, provide support, etc. that the court would enforce.
So if you and she had an agreement regarding treating each other as if you were married, and she can prove it using whatever documents and witnesses there are, then she'd be able to enforce that agreement.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.