My spouse and I share the same email address. We are married, but separated. I want to file separately. How can I?

Email is not required to file taxes.

You can have up to 5 TurboTax Online accounts with the same email address, but different user IDs. So you could create a new account for your separate tax return. But if you do that your spouse will see, and have access to, any emails you get from TurboTax. You might prefer to establish a new email address for yourself, and create a new TurboTax Online account with the new email address to use for your separate tax return.

As mentioned, you and your spouse can prepare your own tax returns under the same Turbo Tax email. You will just create a separate user name. If privacy is an issue between you and other users of your Turbo Tax account, you can create a new turbo tax account with a different email address.

Here is a link with a little more information. Married Filing Separate with the same account