Hello Oynet,
Sometimes when we are at the mercy of emotional overwhelm, it helps to focus our mind on reading information which is more clinical and rational. (Just as a therapist will help us in the direction of rational thinking and away from stress-induced, highly emotional, incorrect thinking).
If you google "Wikipedia Traumatic Bonding" you will bring up the page describing various types and situations of traumatic bonding. There are many varieties and levels.
To keep it simple, and related, I think, to your situation, I recommend reading just these parts:
Under the Context section, in bold print, the information on Intermittent Reinforcement.
Under the Outcomes section, in bold print, the information on Staying In Abusive Relationships.
It has always helped me when I go looking for guidance and deeper understanding, to research. And often the answer has stood right up off the page and spoken to me.
My only other suggestion is to go 45 days no contact in any form (this would include no contact with his mother or mutual friends). Take this time and space to educate yourself about abusive relationships. You can read books by Susan Forward, for example. You can ask your higher power to guide you to the right information.
Hang in there. You are lost in the storm but land and calm skies are ahead.