Tax filing status for an out-of-state NY state student

[elevasil]

Hi! 

I work and live in WA state, and my husband came to the US as an F-1 student and got his green card last year. Past few years he's been studying for his PhD (as an out-of-state student) and working as a researcher at one of the NY state universities. He rents an apartment over there.

Last year we got married, so he started spending more of his time at our house in WA, but he is still renting a place in NY state. All his IDs have our WA address.

We're planning to file joint federal taxes, but we are not sure how he should be filing NY state taxes. Last year he filed as a resident. Based on his flights history, he spent exactly 180 days in NY state. So based on https://www.tax.ny.gov/pit/file/nonresident-faqs.htm, it doesn't sound like he should be considered as a resident. I still don't understand if he's still considered a part-year resident, and how he should be filing the NY state taxes, and if the fact that we're filing joint federal return can affect it in any way. Looking for guidance on this part. 

[RobertB4444]

He'll need to file married filing separately for New York and he'll file as a part year resident.  New York taxes all of his income even if he only lives there part of the year so you'll need to do the New York return first and then take a deduction on your joint Washington return for the taxes paid to New York,

@elevasil