When filing for bankruptcy, married couples tend to file jointly because they are so financially intertwined and their debts are comingled. California couples are especially financially entangled because California is a community property state meaning that all assets and debts acquired during marriage belongs equally to each spouse (except for property acquired by gift or inheritance). So, all of the property you and your spouse own would be included in the bankruptcy estate.
However, married couples are not required to file jointly. In fact, filing separately can be a good tactic for some couples (e.g. newly married couples that have not purchased any significant property together). If you file separately, bankruptcy only affects the filing spouse's credit score. If only one spouse has debts then it may be better for only that spouse to file for bankruptcy so that they can protect the non-filing spouse's good credit.
If you and your spouse are considering filing for bankruptcy please contact an Orange County Bankruptcy Attorney at 1st California Law for a free consultation to determine whether filing jointly or separately would be best for you two.