It's not a kick up the backside you need, it's self-respect to kick in...it's that when someone has pulled you down and beaten on your self-esteem you can't see what they are doing to you. It was gradual and over the course of 4 years. She's hurt your self-respect immensely. It's a very effective thing to do by abusers.
If you get away from her in a year you will look back and see it much more clearly. You will be amazed you ever put up with it. You can't see it as clearly right now because you are still mentally in the thick of it.
That's why you have to save yourself by getting away from her.