Amend your 2019 return and use MFS (Married Filing Separately). There is no requirement to put your spouse’s SSN on your return if you are MFS, only their name.
If you filed 2020 as single, then amend that and use MFS. If you did not file 2020, file it now.
Use an address where you can currently be reached. On the 2020 return, it will ask if you received stimulus checks one and two. You can answer No to that question. The stimulus checks will be added to your refund or deducted from taxes owed.
The third stimulus check can be claimed on your 2021 taxes next year.
