cut your losses now. dont wait for the value to sink any further. depending on when you got into your current wife, you may still have equity you can save. and, with the current exchange rates, you may find a sucker overseas investor to take her off your hands.
either way, dump her, find yourself a rental with a nice attitude and nice amenities. in a couple years, you may either buy the rental or find another for half off. be patient, the marriage mess is only just unfolding.