Would there be any reason that you can think of that I should avoid filing jointly? We are probably going to separate this year. With that being the case, would there be anything that he could do this year 2022 that would come back on me or make me liable if they see that we filed jointly in 2021?"
You state that your spouse didn't make any money. Unless he hid income from you (which if he did, you could claim innocent spouse). Therefore, I'm assuming the income on what would be a joint return is all your income or joint income. I don't see any extra liability from his side that would affect you. You'll pay much less tax on MFJ than MFS.
Again, unless he hid income from you (legal or illegal) there shouldn't be any extra liability. If by chance that it is discovered later than he did in fact have unreported income and you did not know about it; you would be able to claim innocent spouse and not be liable for any extra tax and penalties.
