If your spouse filed a joint return and will not show or share the tax return with you, talk to your divorce attorney. Your name is on that return and you have a right to see the information on the return. You also can pay the IRS to get a copy.
You can get a free transcript from the IRS or for a fee of $30, an actual copy of your tax return.
https://www.irs.gov/individuals/get-transcript
https://www.irs.gov/pub/irs-pdf/f4506.pdf
https://www.irs.gov/payments/your-online-account