Gail Marie
Derek, my unsolicited suggestion is to work through your own stuff and find a solution with your ex by putting your son first...relying on outsiders (ie the court or anything associated) is giving up your own power and can be more costly then you taking responsibility.
Deal with your own hurt and anger you have towards her and for the sake of your child come to a private agreement. It may be the more challenging route to take, but in the long run it will be the most beneficial to your child.