You do not claim your spouse as a dependent. Rather, you file Joint, which you should have done for 2018. Qualifying Widow(er) is a filing status that can be used for 2019 and 2020 if you have a child, stepchild, or adopted child you claim as your dependent. If you have another type of dependent (such as Mother in Law) , then you may qualify as Head of Household instead.
This is is a forum for Turbotax users, so please ask your tax prep company to explain why they handled it the way they did.
