The IRS says the custodial parent is the one who can claim the children as dependents. That would be the parent with whom they spend at least 183 nights in a tax year. It sounds like you are the custodial parent, so no, your ex should not be claiming them.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
