TurboTax accounts cannot be split or merged. You both should start new separate accounts since you are no longer filing joint tax returns.
If the account still has either your email or your phone number, you could contact TurboTax Support to try to get a verification code.
Do you at least have a copy or PDF of the prior year's return that you can use to rebuild the information in TurboTax? If not, you can order one from IRS.
To get a complete copy of a previously filed tax return, along with all attachments (including Form W-2), submit Form 4506, Request for Copy of Tax Return. Refer to the form for instructions and for the processing fee. See IRS Topic 156 for more information.
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