I am filing Married but separate. He lives/works in Canada and has no income at all in US. I live and work in US and have no income at all in Canada. He has a SSN from 16 years ago under special work VISA that was granted for a very short period of time (international sports/coaching). Do I have to provide his SSN if he hasn't used it in 16 years or can I just put NRA? He has never had green card or anything, just the very short special VISA that he worked under for short time and that expired over 16 years ago. We want to do the right thing, preferring to leave him off my return by using NRA instead of SSN if possible. Will not be claiming him as exemption either.