Turbotax recommends that when you change filing status (such as married filing jointly to married filing separately) you need to create a new account. It is very difficult for the user to remove all the data of the former spouse from the file.
In this case, if your ex (or soon to be ex) has control of the Turbotax account, there is really nothing you can do to remove that information. (And in fact, for any past returns that have been jointly filed, its not possible to remove because it was already filed with the IRS and for completeness, your file must match your returns.
If you are concerned that your spouse will mis-use your prior year financial information, you need to discuss that with your attorney.
