I've completed my tax return and wish to prepare my wife's separately. On the welcome page I see 'my wife/partner and me'. Should I use someone else?

You can double check if you have prepared the returns together or separately. Opening the return and clicking Setting Up in the left side menu. If you see “Addition Information about [Spouse Name]”, then you have prepared the return only for yourself. If you see a lot of things doubled, like “[Your Name]’s Personal Information” and “[Spouse Name]’s Personal Information”, then you have prepared the returns together.

Unfortunately there is no way to separate the returns once you have started a joint return. You would have to create a new return and make sure that when it asks you if you are married, to choose to prepare the return only for yourself.

I choose 'someone else' and it seemed happy