In 2008 I co-signed a student loan for my son to attend school. Since then, my spouse and I divorced. Is she responsible for any part of this loan?
That issue should have been raised and resolved at the time of the divorce.
In family court yes in reality your name is on the loan so they will come after you if there is a default.
Whoever signed the Note is stuck. If ex-Wife did not sign and there is no court Order stating otherwise she is free.