You can request copies of your tax returns from the IRS. I don't know what their policy is on providing copies to ex-spouses. https://www.irs.gov/Individuals/Get-Transcript
To access your Turbotax files, you would have to contact customer support and have them reset the passwords on the accounts. I don't know what their policy is either, regarding ex-spouses. If they agree to provide access, you will likely have to fax in proof of your identity.
