The ACA Premium Tax Credit is based on household income. If you married in November and filed a joint return then the combination of your husband's income and your income is used to calculate and reconcile the premium tax credit. Based on the combined income you no longer qualified for the supplement you received and you have to pay the supplement back.
The premium tax credit would have nothing to do with the fact that your husband was covered under his employer's insurance. The premium tax credit is based on household income reported on your tax return.
ACA Marketplace Insurance
