*You* could not give a 8332 unless the child physically lived with you so the 8332 that you gave to your ex spouse meant nothing since you had nothing to release. She was the custodial parent all along. So you revoking a 8332 that did nothing, would not be necessary.
Your divorce decree seems (I am not an attorney and only an attorney can give you legal advice) to specify that your Ex spouse give you the 8322. The decree also does not call for an "open-ended" 8332 but "for each subsequent year". If the child lives with your ex, then you should ask *her* to issue you a 8332 so she would be in compliance with the decree. If she refuses, I suppose you could go to the family court that issued the decree for a contempt charge.
(BTW, once a child becomes 18 (or the age of an adult in your state if not 18) then the concept of custody and the 8332 becomes moot and the child can only be claimed by the parent that the child actually lived with.)
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
