Kay, you say you have been the custodial parent since the child was born. Is that established by court order? Is there a court order that specifies in writing that you are the primary custodial parent? Or has there just been a general out-of-court agreement? The answer to this question is vital for us to be able to answer your question.
Generally the term "kidnapping" is not applied unless the child's whereabouts are unknown. At this point the disagreement is civil, not criminal, or so it would appear on limited information.
Get a lawyer. The odds are in your favor, but do not delay.
