Just so I’m clear, originally you had the loan, then it was refinanced into your ex’s name a few months ago, both of you are in title, and you have another loan on another property, solely in yoru name, is this correct? If so, if she stops paying the mortgage for the apt, it will not have any bearing for the loan you have seperately, if she’s on the note by herself, she has sole reponsibility for the mortgage, but she can walk away from the property or default and you run the risk of losing title to the property

You would still be half responsible for the original loan.