Legal Question in Real Estate Law in California

You can sure try, but I doubt you'll succeed other than by filing a divorce action and seeking division of the assets. Consult with local divorce attorneys.

The only way I know to get a court order against a spouse regarding community real property is to file for legal separation (if you don't want to divorce) or for dissolution (or annulment) of marriage (if you do want to be divorced). Perhaps if you had a written agreement for some other business arrangement you could enforce it in a regular (civil) proceeding, but it looks to me as though your solution lies in family court.

Assuming this is headded for divorce, she owes you half the monthly cost of owning the property, but you owe her half the rental value of the property if you are the sole occupant. There is a strong presumption that the two zero out. Once you divorce, one of you will have to refi-the mortgage, or you will have to sell it.