To reset the passwords, you would have to contact customer support.  See the bottom here.  I don't know if they will do that since it would lock out your ex, and this information belongs to both of you.

It is always recommended that after a divorce, you make a new Turbotax account and start clean, because bad things can happen if you try and turn a joint account into a single account or a joint account with a different person.  So the only reason to get access is for copies of past records.

If you need proof of what you filed, you can get a transcript from the IRS for free.  If you need detail worksheets such as for depreciation or certain carry-overs, I think you would probably get better results by asking your ex to download and give you the PDF for "all forms and worksheets" for each prior tax return.  Ask through your attorney if needed.

You can try and take over the account by calling customer support.  You will also need to fax in proof of identity and it may take a few days, if they honor the request at all.

https://ttlc.intuit.com/replies/3300041