HI. If your ex used a downloadable version of TurboTax, the only copy would be the copies saved to your/his computer. TurboTax has no copy of returns using a downloaded version. If you have access to the computer used to file your taxes, try searching the computer and external drives.
If you still cannot find a copy you can request a copy from the IRS here:
https://www.irs.gov/individuals/get-transcript
