It sounds like you have already moved away, which is normally not the best way to handle the situation.
If your ex-husband has custody rights and did not agree to allow you to move to another state, you could be forced to come back or to give up custody.
Even if your ex is not a great parent and your children hate visiting with him, he has legal rights and by taking the children without his permission, you violated those legal rights.
It will usually not look good for you in court if you moved away without arranging visitation, getting his permission, or seeking the permission of the court.
It’s likely that moving away will not solve the problem of visitation being traumatic for your kids anyway.
Unless your husband no longer wants to see your children after the move, which is doubtful, the court will award visitation to him, possibly for long periods of time since you will be out of state, which can make travel easier.
The better course of action would be to take your children to a therapist to deal with the issues and to see what can make the situation easiest for the kids.
You can then ask that the visitation be modified as recommended by the therapist.
If you do find yourself in court over the visitation issue, you need to present a strong showing about what arrangement will be in your children’s best interests.
You may choose to produce evidence about the visits with their father being traumatic for the children.
You should also be prepared to show why the move will be in the best interests of your children.