I'm fairly pissed for you. I'm not giving advice at the moment...but if it were me in your situation, I would NEVER get back together with a spouse that withheld my child from me. There is far too much of this in our society, women that view kids as their possessions. I'm hopeful that you'll get an agreeable legal solution to all this.
You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer