Without a full and complete review of the documents an answer would be impossible to render.
Unfortunately, in the small space provided for questions one is unable to get a full background of the story. In the situations such as you are explaining you should immediately seek the counsel of a capable attorney that practices in this area of law or if you cannot afford an attorney, you should seek a social service organization in your area. This answer is general in nature and does not form an attorney client relationship. If you would like to get more information on this topic or to establish an attorney client relationship please contacts my office.
An attorney would have to review your employment contract to determine what grounds, if any, you would have to break it.
Disclaimer: This answer is provided as a public service and as a general response to a general question, it is not meant, and should not be relied upon as specific legal advice, nor does it create an attorney-client relationship.
Of course, I would have to see it in the suit brought by her husband to answer this fully. However, as a general rule money in a joint checking account is owned by both parties to the account. Furthermore, it sounds as if the money, and possibly the debt, or marital, in which case the divorce judge would sort out who owes who.
Your situation involves important and complicated matters of law and fact. I urge you to consult with a lawyer on this matter.