menaed, what you are going through is totally normal!! Evrrything you wrote I was going through, word by word!
You are human, you think and act like human. This is human! What they do is robot-like. Un-human.
You may feel like a psychopath as well. His goal is to make you feel like one, and make you look like one. These people are gonna do anything, literally anything to hurt you. It may not always be on purpose, but thats even more to fear. Cut everything that attaches you to him. I know its too hard to think about it right now - but try with anything. Something small, maybe, a photo, a gift anything. Just throw it out thinking you're throwing it out of your mind. And force yourself to never think of it again.
What I've done (and still do) and found very helpful was something I called "overwrite". Anytime I went to places that reminded me of him (no matter if good or bad memories) - I tried to scan the place and make a memory of sth new that happened there. Like just today - I am in a new city, and met with a friend, and we met at this well known place, and when I got there, I got upset and really sad for a moment, because I saw just this one bank that we (me and the Psychopath) sat on this one time... But then I realized, this is MY place, this is MY spot. Im not gonna let him here anymore. So I looked around to find my friend and there she was. And from now on, its not a place where me and the Psychopath would sit that one time. It is the place where I met with my friend, and thats how Im gonna remember it!
Of course, you have a child. Thats tough. I cannot even begin to try and understand how you must feel about it. But I would recommend trying to think of it as YOUR child. Your, and thats it.
If you try hard enough, beautiful things will happen to you. I am living proof!
You can handle it! And whenever you feel like you cant, we're here for you!