Legal Separation and Health Insurance coverage in CA.

Who told you that? After a divorce, when your ex-wife is no longer your wife, she would not be a "family member" eligible for employee and family health insurance coverage through your company. But it is my understanding that one reason a couple might get a Judgment of Legal Separation is to enable the unemployed spouse to remain on the employed spouse's coverage. Is it a provision in the health insurance policy of your employer's insurance carrier that states that after a Judgment of Legal Separation, your spouse can no longer be covered? Please advise in a comment under this answer after inspecting the policy. Also, if you get some legal authority for the proposition addressed in your question, please share it in a comment under this answer.

The short answer, and the practice of attorneys pursuing legal separation, is no. Please consult again with HR, directly with the insurance provider, and with a local lawyer.