Hi Liltom,
If the card is in your estranged wife's sole name, and you have no party to it at all........then stop paying it!! you are being way to generous by paying off her debt.
I believe that the bank/debt collectors can chase you wherever you may be living. The country doesnt matter. Finding her may pose a problem..unless of course you accidently provide the bank with her address and telephone number. If they were to be able to confirm where she lives, then they will pursue her.