When you are legally married and living together you can only file your tax return as either Married Filing Jointly or Married Filing Separately. There is no such filing status as Married Filing Single.
Amend your tax return and change your filing status to Married Filing Jointly. Then your spouse can enter their information on the joint tax return.
Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.
See this TurboTax support FAQ for amending a current year tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-federal-tax-return-curr...
