You will need to file a 2020 tax return under the status "married filing separately." E-filing is closed, so you will print your return and mail it. You don't need to file a state return.
At this point, you would need to buy Turbotax to install on your computer from a CD or download, the online program is closed so they can change over to 2021. Turbotax only sells the Deluxe version for $80. You may be able to find a leftover copy of the Turbotax Basic CD for 2020 from an online retailer for lower cost. Or, because the return is simple, you can download the forms and instructions from the IRS web site and prepare your return by hand for no cost. If you have no income, you are only claiming the round 1 and round 2 payments on line 30.
Be aware there are two different social security disability programs. SSDI will pay if you are disabled and worked long enough before you became disabled to qualify. There's no reason to not apply if you worked long enough to qualify in the system. Your spouse's income does not affect your SSDI benefit. If you become able to work again, you can give up the benefit. (You only have to certify that you are unable to work due to a condition that is permanent or will last at least one year. If you can certify that now, and your health improves later, you can give up the benefit and return to work.)
https://www.ssa.gov/disability/
There is also SSI, which is need-based. Hiding a spouse's income to qualify for SSI would be benefits fraud.
I won't attempt to advise you on your personal situation except to point out something others missed—if you do file a joint return, then you are taking joint and equal responsibility for all the income, deductions, and taxes owed, and you are equally responsible for any misstatement or errors, even if all the income is your spouse's. While it will generally lower your tax to file jointly, there is a responsibility involved. If your spouse is keeping their finances separate from you and you aren't comfortable signing a joint return, that's a valid concern.
