from form 2441 instructions
Special rule for children of divorced or separated parents
or parents who live apart. Even if you can't claim your child as
a dependent, he or she is treated as your qualifying person if:
• The child was under age 13 or wasn't physically or mentally
able to care for themselves;
• The child received over half of his or her support during the
calendar year from one or both parents who are divorced or
legally separated under a decree of divorce or separate
maintenance, are separated under a written separation
agreement, or lived apart at all times during the last 6 months of
the calendar year;
• The child was in the custody of one or both parents for more
than half the year; and
• You were the child's custodial parent. (This is the problem)
Generally, the custodial parent is the parent with whom the
child lived for the greater number of nights in 2023. If the child
was with each parent for an equal number of nights, the
custodial parent is the parent with the higher adjusted gross
income.
Generally, the noncustodial parent can't treat the child as a
qualifying person even if that parent is entitled to claim the child
as a dependent under the special rules for a child of divorced or
separated parents or parents who live apart.
