No, if you were not married during that tax year then you would not combine your tax information on the same return. You would file 2 completely separate returns for 2019.

We have already filed our 2019 returns. This question appears on the 2020 form

Yes, when you combined households, you combined it all. Add your separate 2019 numbers together. Congratulations!

Related:

• PA Schedule SP Eligibility Income Tables
• Instructions For PA Schedule SP - PA Department of Revenue