In order for someone to help, you need to provide more details. What information have you gleaned about your husband's parents? The birth certificate of your husband's parent -- the child of your grandmother -- might very well contain the name of his grandfather. Remember that it's important to work backward from yourself, or in this case, from your husband, obtaining documentation and proof as you go.
You might receive more help on the appropriate California message board from someone with local knowledge. Provide enough information to enable someone to help, e.g., your ancestor's full name, the date of the marriage(s), and the names of the husbands on the marriage index that you're viewing. Saying where you have seen this index and attaching a copy of the index would also be helpful.
-- board admin.