There are fewer things as painful as when a child wants or chooses to live with their other parent. If you have been placed in this situation, here are a few things you can do:
Recognize the pain. Give yourself the freedom to grieve the loss. It is heart-wrenching to be rejected by your child and it's OK to feel pain and sadness. Journal, open up to friends, visit a counselor. Take tender care of your heart.
Weigh your options. Depending on the age of your child, your response will differ. Here are some age-appropriate considerations to keep in mind:
Elementary school and younger: Your child may threaten to move in with your ex-spouse as a manipulative tactic. It could be he is testing his limits and this is one way to see if you are going to stand by your rules. If you cave in on a consequence as a result of his threat, he'll learn to use that to his advantage. Gauge his behavior. Is he talking about moving when he's just gotten into trouble? Then stick with your consequences. Or is this something that comes up when the waters are calm? If so, ask him why he would like to move in with the other parent. Talk through his reasons and give him room to express his desires. Try not to communicate your hurt — it is likely he is just yearning for more time with the other parent, not rejecting you. If you are having a tough time discerning his request, don't hesitate to seek professional counsel.
Teenagers: When a teenager wants to move in with the other parent, the situation can get a little more difficult. Older teens may have the ear of the court system; a judge may disregard what you feel is best. Even if the courts are not involved, teens need special consideration. Giving them the freedom to experience the other home may be just the thing to help them appreciate you. Discerning the optimal living situation can be difficult. Your particular case will be unique, so make the decisions based on as much information as possible. An informed third-party counselor could help you work through the details to come up with the best course of action.
Know when to fight. There are times to set boundaries and protect your child. If your ex-spouse is a danger to your child, no matter your child's age — through physical, emotional or sexual abuse — you must guard her from being harmed. Consult a counselor, hire a lawyer, do whatever you need to do to make sure your child is not in danger.