I found this point in the Nebraska legislature:
A marital debt is one incurred during the marriage and before the date of separation by either spouse or both spouses for the joint benefit of the parties. McGuire v. McGuire, 11 Neb. App. 433, 652 N.W.2d 293 (2002).
https://nebraskalegislature.gov/laws/statutes.php?statute=42-365#:~:text=A marital debt is one,joint benefit of the parties.
Unless the debt was incurred before they got separated and it was for the joint benefit, I don’t think she has to pay anything. She should hire a good attorney though to protect herself