I’m married, went on medicare last year, my wife stayed on aca. Are we required to file jointly? We exceeded 400% of aca income so when we file jointly we are penalized

[Coleen3]

Unfortunately, this may not be the solution. You can try mocking up MFS returns for both of you to see if it works any better but read the text below.

Yes, but there are special rules for allocating when you are married filing separately that you should review. 

Married Filing Separate, Spousal Abandonment/Suffered Domestic Violence

If you are married but filing separately because your spouse abandoned you or you suffered domestic violence, it's usually 50% of premiums and the advanced payment of the premium tax credit. The SLCSP percentage is usually left blank.

Married Filing Separate, other situations

If you're married but filing separately and are NOT a victim of domestic abuse or spousal abandonment, then you do not qualify for the premium tax credit. You must generally repay all Premium Tax Credit paid in advance as a discount health plan that covered only the people on your taxes, and half of the PTC paid in advance for a policy that covered at least one person on your taxes and at least one person on your spouse's tax family. However, there may be a cap on the amount of advance payment of the premium tax credit you have to repay.