If you separated or divorced in 2017,
the CRA will still require your spouse’s information.
If you separated or divorced before
2017, you say "No" to the question "Did you separate from your
spouse/partner in 2017?".
To make changes, select “Marital Status”
from the “Setting Up” tab. Choose the correct options and click the “Continue”
button to save your information.
If you can’t see a “Setting Up” tab, use
the grey “Back” button to go backwards through the pages until you get to the
“What's your marital status?” page.
I’m separated or divorced. Why am I
being asked for info about my former spouse/partner?
https://turbotax.community.intuit.ca/replies/3425400
What do I do if I don’t know my spouse’s
income? https://turbotax.community.intuit.ca/replies/2647950