If you owned your business before marriage, you may have assumed that it all remained your separate property after marriage. Unfortunately, unless you entered into a prenuptial or premarital agreement that provided otherwise, under California law a spouse can, and most often does, claim a community property interest in the business.
California law recognizes such an interest, and has developed a complicated set of rules to determine what that interest, if any, might be, depending upon the type of business.
This is probably the most important reason business owners and professionals, no matter how much of a romantic they may be, should insist upon a prenuptial agreement being signed before marriage. Think of it as business or marriage insurance and a cost of doing business.
If you did not enter into a prenuptial agreement and you owned a business prior to marriage, you absolutely need an experienced attorney who specializes in business and professional divorces, and an equally experienced forensic accountant, involved in your divorce proceeding.