I got the answer from the IRS tax law experts! If a child is at the age of majority (emancipated) under state law, they are considered NOT living with either parent. In my case, since the child was 21 years old most of the year, he is considered not living me me or my ex. Therefore under the tie breaker rules the rule about whom the child lived with longer does not apply. In my case the next rule would apply which is based on the higher AGI for the year.....which is me. So I actually get to claim the child and my ex does not.
The IRS tax law expert had to research this quite a bit as well, but that was their conclusion.
