You know, the "break" idea is good because that way you don't have to terminate the friendship just yet.
Tell her you are coping with so much with your divorce you really can't "be there" to hear all of the stuff because you are dealing with so much of your own, and step back a bit.
After some time passes, you can see if she is still in the same "complain but don't change" loop with you and act accordingly. No rush.
How does a quiet and peaceful home for the holidays feel, by the way?