You can determine your share of the tax liability by using these methods:

TurboTax Online

1. Enter all of your information into the return first.
2. Note the tax liability. 
3. Then add the information on your wife's business to see how the figures change.
4. If you have already entered all the information, note the tax liability and then delete the Schedule C from the return.  [You would have to reenter it before filing.]

TurboTax CD/Download

1. You can view the What If Worksheet in Forms Mode.
2. Go into Forms Mode by clicking the Forms icon in the top right of your screen.
3. Click the Open Form icon, above the Forms in My Return list.
4. Click the plus sign next to 2019 US Form 1040.
5. Scroll down almost to the end and click What If Worksheet.  
6. The worksheet will appear on the screen to the right.
7. Click Copy column 1 to column 2. (Column 1  is populated from your return -- you will make any changes in column 2)
8. Delete the business income on line 12.
9. Scroll down the list and make any other desired changes.
10. You will see the difference in tax liability at the bottom of the form.