Yes. The IRS will only grant one dependent deduction per social security number. I defer to the advice of your divorce attorney for your recourse in Family Court.
If your ex would agree to amending her filed return immediately and only claiming one child, she will save herself penalties and interest and lengthy correspondence with the IRS.
You, in the mean time, can properly file your tax return by mail claiming one child as agreed. The filing will take about 16 weeks for the IRS to process. It would be useful to get Form 8332 signed for the noncustodial parent from the custodial parent.
To find this form in TurboTax, follow these steps:
- From the left menu, select Federal>
- Other Tax Situations (third tab across the top)
- Scroll down to All Uncommon situations and find Other Tax Forms and click Show more
- Find Revocation of release of claim to exemption for child of divorced or separated parents and click Start to begin the process
