As a permanent resident cardholder, previously filed MFJ, spouse has not been to U.S.in 3+ years. I still support child and household in Mexico How do i file?

Not acting as a married couple any longer and have both moved on but have not gone through any legal proceeding as it is mutual and not in any way hostile. i still support my household and child in Mexico as i send money regularly and spouse doesnt work.. i fully support the household in mexico and my own in the US