Ok. Thanks. I just want to make sure that I understand your situation.
If your ex has filed bankruptcy and had her obligation to pay this debt discharged, she shouldn't have any claim against you because your failure to refinance or pay will not affect her in any way because her own bankruptcy has eliminated her obligation to pay the debt.
If she didn't discharge her obligation to pay the debt/mortgage, then if you cannot refinance the mortgage, your ex could file a motion to hold you in contempt of court for failing to refinance the debt. However, if you can prove that you cannot get the home refinanced because of the negative loan to value ratio, the court would likely try to work with you, or even allow you to offer the home back to your ex or some other solution.
Also, if you do allow the property to go into foreclosure, and she is required to pay some deficiency amount (difference between the debt and what the sale produces), she could ask the court to order you to pay that amount on her behalf.
The best thing for you is if she had the debt discharged in bankruptcy. I that case, you could walk away without owing the mortgage (since it's not in your name) and you wouldn't have to file bankruptcy.
Also, if you were to file bankruptcy, it would relieve you of the debt there would be no obligation for you IF she discharge the debt. IF she didn't discharge the debt, bankruptcy would not help because bankruptcy cannot discharge a divorce award regarding property division/support, etc.
As for your business, if it is incorporated, a personal bankruptcy should not affect your business UNLESS you have personal guarantees
or some other individual/personal ties to the business that would affect your company's credit.
I hope this covers all of your questions, but if you need something else, please let me know.