If the original lease for the former rental that you had with your former wife is on a month-to-month basis is still residing in the unit belonging to her aunt, where you moved out years ago, you would not be responsible for any unpaid rent.The key is whether or not the landlord knew of your move out. Most likely, the aunt landlord knew about your move out and end of the written lease. Whether or not your name is on the expired lease does not matter. What matters is that you have not resided in the unit on a month-to-month basis for years.