Are you co-dependendent/addicted to him/her?
Do not have children together, is this stopping you from leaving? This is still no excuse. What is it teaching your children about relationships?
Even if you do not currently have children what if you did have children with this person in the future. It is not likely to be a healthy family system as this person is likely to be a narcissistic parent too.
This person is never going to change. The only person you can change is yourself. Any other efforts are a waste of your valuable energy.
The more you tolerate the more you will be controlled, this person has chosen you because he/she knows this.
Why have you stayed with someone so toxic and controlling? You need to get therapeutic support to help you become independent to give you the choice to walk away from this toxic relationship.
Unfortunately the only way I see you stopping this narcissist from ruling your life is by you working on yourself, so that you find your voice and perhaps eventually walk away via having no contact.
For more information about the subjects covered in this blog, contact Margaret Parkes - phone: 086 832 0422 email: firstname.lastname@example.org