Please do not ask your child to deliver messages to your ex. This is not the job of a child. Work on finding enough communication to leave your child out of it. If you need to find a third party to help you do this, then find someone. Do not put your child in the middle.
Childhood is a special time.
It should be a time of innocence and playfulness, not anger and fear. Let's work together to protect our children. It is important.