This credit issue was with my ex husband over 10 years ago and he had gambling issues and took advantage of my credit at the end of our marriage. At that time I didn't know, moved away, and was not aware of any cases against me until years later when I try to purchase a home.
Depending on your divorce settlement agreement, you may get some relief in the divorce court. Depending on your financial situation, you might be able to negotiate a settlement of the amount. Also depending on your financial situation, you might be eligible to file bankruptcy and discharge the debt completely. Talk to a competent bankruptcy attorney asap and see what is your best option.