Thanks for the reply!
My husband actually has CA income from his internship.
I digged around a little bit into both state's policies. This is what I ended up doing:
CA:
as stated in https://www.ftb.ca.gov/file/personal/residency-status/part-year-and-nonresident.html
"A nonresident return is required when a resident spouse and a nonresident spouse wish to file a joint return."
Since my husband is not a CA resident, we filed jointly for a nonresident return.
PA:
as stated in https://www.revenue.pa.gov/FormsandPublications/FormsforIndividuals/PIT/Documents/dfo-02.pdf page 17.
"However, you can file jointly if you both elect to file as PA residents and meet all other requirements for filing jointly."
We elect to both file as PA residents and used our taxed paid to CA as credit.
