My ex has had custody since 1998.My son is 17 and doesnt want to move.He has been here since elementary school. He stays with me 5 days a week now.

  In a hearing, you would first need to prove that there has been a material change in circumstances, then you would need to prove that modifying the current order is in the best interests of your son. Based upon the circumstances you've described, it appears likely that there has been a material change in circumstances since the entry of the court's last order:  your son is significantly older than he was in 1998 when (I presume) the last custody order was entered; Dad has remarried (again); and your son is close to graduating.  You could file a motion to have the court review or amend the order.  The forms are available from your local juvenile and domestic relations district court clerk's office.  You would: (1) describe the current custody/visitation order; (2) describe what you want the order to be (sole legal/physical custody; and (3) why you want the order changed.  Once a material change in circumstances has been established, any proposed modification to the prior order would be based on what is in your son's best interests. You've indicated your son doesn't want to leave.  At 17, he has a say in the matter.  The age of 14 is considered the "age of discretion" at which time the child's wishes are given considerable weight.  However, this is only a rule of thumb and is always subject to change based on the unique circumstances of each case. he above response has been provided for general guidance on matters of interest only and is not intended as a legal advice.  No attorney-client relationship has been created between the reader of this response and The Law Office of Karen M. Holman, PLLC.