Your situation sounds very complicated. You realy need to consult with an attorney and go over all of the details. I would suggest that if you have a divorce attorney you consult with them. If she is unaware of the problem and you fail to disclose it, there could be serious fianacial complications for you and of course her.
Be prepared to give the attorney a copy of the document you signed.
If you appeared to have the authority to bind your wife's company, the vendor can probably hold your wife responsible for your contract, under the doctrine of apparent authority. Otherwise, people would all the time claim that some unauthorized person signed a contract that they don't want to pay.
A creditor cannot usually secure a levy (either a garnishment or sequestration) against a bank account without first having a judgment. If the creditor in this situation has no information about your wife's accounts, the creditor probably will not try to seize them without first obtaining a judgment.
I suggest that you approach the creditor and bare your soul, and indicate that your soon to be ex-wife was not responsible for the contract or the debt and that you are. You may be able to negotiate a reasonable result with perhaps a termination of the contract and a payment plan. Otherwise, the creditor may file suit and the cost of lawyers will make the matter much more expensive.
Since you had apparent authority to execute the contract and since her business is receiving the benefit of the contract, the creditor will probably prevail. If a judgment is taken against her and her company, they will be able to go after assets like bank accounts to satisfy the judgment. Your best bet is to hire a lawyer to work out a deal with the company and informing them of the fraud. They will probably settle for less than the full value of the contract.