Is anyone else choosing to stay with their narcissistic boyfriend/husband if so how are you handling it?

I have been with him now for 6 years we have a 3 year old son together. I figured out he was a malignant narcissist a year and a half ago. I literally have nowhere else to go, my own family won't take me in because they HATE him and are afraid if I stay with them he will come around to see his son. So I am always educating myself on his disorder to help keep my sanity, and I threaten to leave him constantly to try and keep him under control but I am so unhappy dealing with his emotional abuse. I was just wondering if there were any other women out there dealing with this too and how you cope day to day. Thank you.