With regard to IRAs, if you were not to be responsible for the taxes on any distribution of your ex's share, the divorce agreement should have specified that your ex's share of the IRA be transferred trustee-to-trustee to an IRA in your ex's name. Such a "transfer incident to divorce" is neither a distribution nor a rollover and is not reportable. Because the distribution was paid to you, you are responsible for including the distribution on your tax return.
