I would strongly suggest that you seek help from an accountant in your area and bring with you a copy of your divorce agreement.  Although it seems to stand to reason that if you are paying half of the taxes you should also have the benefit of the deduction, one would really need to read the agreement as a whole to see what the intent behind it is and then check the tax code to see if it is possible to do as you want.  I am assuming here that you also are still the owner of the house and that is also a plus for you.  Get some advice in your area.  Good luck.