When you get married in California, you have created a "community" and both members of the community own everything equally. All property received by members of that community belong to the community and all debts incurred by members of that community are owed by the community. The only things that stay separate are 1) what you had before you joined the "community", 2) what you receive after you leave the "community", and 3) what you receive as a gift, inheritance, or bequest.
So, while you might think that because you have operated separate bank accounts and separated your billing, it doesn't matter when you get divorced. Every asset and debt incurred by the community is equally yours and equally theirs, unless you have a valid prenuptial or postnuptial agreement saying otherwise.
Thus, when you get married in California, don't take the financial aspect of the marriage lightly. Get your ducks in a row and educate yourself about what is in store for you, so that you can enter your marriage in a positive, informed mindset. Maybe even consider getting a prenup to better delineate whose property belongs to who.