I do not think anything is wrong with feeling anger. It is probably the only emotion I am able to feel lately. And I am just that. Angry.
But we must remember that our feelings are just feelings. Given the circumstances of our ex's, it is expected to be angry. But that doesn't necessarily mean that we have to go punching car windows out or going to their house to see who is there tonight.
Accepting is a big part, and you have to know that the cheating, lying, stealing, etc will not stop. Nothing you or I could do to make it stop. Of course that makes us angry. Allow the anger to serve the purpose of what its doing- keeping you away from the turmoil and tragedy.