Greeneye, I'm 3 years + into a situation similar to yours. My advice to you is simple: get the hell out of that house. Walk away from it, completely. Stop paying the mortgage, house insurance, mortgage protection etc. Let your ex deal with it. Let the bank chase him for the money. He won't be long copping on then. You are not obliged to pay rent in your new place and continue contributing to the mortgage. There's nothing forcing you to contribute to that mortgage except your own good conscience. Just stop. And then wait and see what happens.
Things will happen fast - both your ex and the bank will be forced to start taking action.
If you dont' do this then believe me, years will pass and you'll be paying the full mortgage and insurances while your ex has buggered off (or worse, stopped paying but hasn't buggered off)