How can I move out of state with my kids if my ex won't agree to it?

Relocating without either spousal consent or a court order could lead to loss of custody; I strongly advise a consultation with a family law specialist.

You have to file a motion to get permission from the court to relocate the children. This is a very difficult area of the law. You must meet the legal burdens necessary in your pleadings. You will do better with an attorney, especially if you know your ex is going to fight you.