If the order provides that father and grandparents share physical custody of the child(ren) subject to mother's supervised visitation, then mother is the noncustodial parent. But, if the order specifically provides that grand parents have primary physical custody or more overnights than father, then both parents could be noncustodial. The actual language of the order and the reason for seeking the determination is necessary to provide a complete answer.
If this question is an effort to determine a child support issue, and grand parents are the primary custodians of the child(ren), both parents may be liable for child support to the grandparents.See question
Spousal support and child support should be addressed in any stipulation agreement entered into by parties looking to separate. There are statutory factors that must be considered when a court deals with these issues. Additionally, Virginia has a presumptive guideline for child support that needs to be calculated in all cases. You should contact an attorney who regularly deals with these issues so that you can be sure that your agreement addresses both your and your children's needs.See question
If there was a previous order entered by a court, your child's father would have to show a material change in circumstances in order to have legal and physical custody addressed by the court. The fact that you have had sole legal and physical custody of your son since birth will be a factor that the Court will give considerable weight.See question