AS, if she's done, why hasn't she filed? I understand you making the decision to move on, but all the stuff you have said about her never changing is just an educated guess at best. You don't know what she will do in the future.
Like the others here, I wonder if you are trying to convince yourself that you feel better and are fine with things. It really sounds to me like deep down you are angry. I would be too. I am.
You are right in stating that each person has to choose for themselves when to pull the plug when the marriage is on life support and there is very little if any sign of life. None of this is easy. Whichever way you go, I wish you the best.
