Legal Question in Real Estate Law in California

Yes, provided that you can do so without creating a "disturbance of the peace," although you might owe your ex-boyfriend his reasonable cost of 14 months of cat food. The more important issue between you will be how you'll eventually divide your co-ownership of the house. maybe it is time to consider winding up the co-ownership, which can be done voluntarily, or if necessary, involuntarily (on his part) by your asking the court to "partition" the property. This is done through a court-administered sale, with the net proceeds being divided "fairly" between the former co-owners by court order, taking into account any unequal costs borne or rents received by the parties.