If you have made the election to be treated as resident alien last ear, in order to file a joint return, that election is still valid. If you do not want to file as resident alien, you need to revoke that choice and you cannot use it again in the future.
https://www.irs.gov/individuals/international-taxpayers/nonresident-spouse-treated-as-a-resident
Anyway, what is your and your spouses visa status and when did you both come to the US?
