My ex-wife is the custodial parent of our 3 daughters. Our divorce decree states that she can claim 2 of the children on even years and 1 on the odd years (the opposite is true for me). She was remarried in 2013.

If she has no annual gross income, can she can still claim them as exemptions and receive an income tax refund? If she files with her new husband (and she still has no income) can they claim our children on their tax return and receive an income tax refund?

If the answer to the above two questions is no, do I have any legal standing to demand that I claim all 3 of our children?

(We reside in the state of Michigan)