You'll need to completely begin a new return if you were divorced in 2018. See the information in the TurboTax FAQ below.
https://ttlc.intuit.com/replies/3300911
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***
