C.V.
Sorry to come off as harsh, but the original agreement with the bank (the mortgages you have in place) are decisions you made. In good faith, you agreed to the price and you agreed to the loan repayment terms. I think it's irresponsible to feel like the bank should accept less in return from you because you don't feel like paying what you said you would or because you could get a better offer elsewhere or because your soon-to-be-ex might get something nicer.
Between you and your husband, you either need to decide to sell the house (sounds like at a loss) or keep it for one of you. You are lucky that the bank would modify the loan to $400/mo less to the point where you could afford it. Some people can't even get that break in this economy. If you short sell or foreclose, you aren't going to be able to get credit for many years, nor should you. All of your credit remarks will be around for at least 7 years, and banks are now pushing to make that time period longer.
Sorry that it looks like you might have to go back to work even if it's hard for you, but why should you be entitled NOT to work and earn for yourself and your children, especially if you can find a job? There are lots of working mothers who might rather stay at home with their children but have to earn money to support themselves. No one promised that life would be easy or a free ride. It looks like things are tough for you now. I wish they weren't, but looking for an easy way out isn't the answer.