Is there a way to see what each person's income was for a past year? Not the combined amount?

You would have to look at the actual W2 or 1099 forms you got.

If you filed a joint return, the tax form only shows the combined amount; it is not broken down by how much income each spouse received.   Your own W-2's or 1099's---which you are supposed to save for your own records-- are your best way to see income per spouse.   You can look at the worksheets that are part of the pdf of your tax return to see the W-2's and 1099's that you entered.