This is not something you can do by yourself. This is the case of law and court, but there is a way you can handle this situation. Either you can prove your wife wrong and clear that she cannot handle your child and she will not be successful to take care of him. Or you can appeal to the court to provide you with custody of the child. The court will decide what should be done and what would be good for all of you, you will have equal rights with your son and you can meet him anytime you want. You can ask the court for this permission and ask your wife not to go against the court’s decision.