What happens if my child prefers to stay with one parent even thoguh there is a court order for shared custody

I am sorry you are having these problems with the father.  However, you are in a good position to get the relief you need. Your court order is the  'blueprint' or guidelines for all matters relating to custody and timesharing (visitation) between the father and your child. If he is blocking your timesharing by taking the child from you without permission, then you can return to court to enforce your rights. On your other question, the preference of the child as to which parent with whom the child wishes to live is only one factor in the court's decision to change custody. That depends on the age and maturity of the child, the reason for the preference and, ultimately, what is in the best interest of the child. If this involves a very young child, the court may appoint a guardian ad litem to interview all involved and make a recommendation to the court. If the child is older (16 and above, typically), the preference of the child may be the key factor.  

You can file a motion to show cause why the parent should not be held in contempt of court.