Usually with a long term relationship I would recommend couples counseling. In this case it is obvious that would not work.

You do realize your children are also being subject to emotional and verbal abuse also in all this? You need to make it clear to your children that you are their Dad no matter what happens. The children would in fact be better off with you as far as stability goes. Whether they go with you or stay with Mom, you are forever their Dad.

That being said, you don't sound ready yet to leave. Please document the abuse and call the police if you need. It sounds like your wife has some issues especially as she uses self harm as manipulation also. You might need to call the police for her to receive mental health treatment. Look into psychotherapy for yourself also.