Yikes! You have got yourself into a mess.
First of all, head of household has a special meaning on a tax return. It does not mean that the person is the breadwinner or the person in charge of the household. Head of household is a special filing status for a single person with a child. In some cases it can also be used by a married person with a child who does not live with his or her spouse. But if you and your husband live together, neither of you can file as head of household. The only filing statuses you can use are married filing jointly or married filing separately.
Are you saying that your husband had income that he does not want to report? That, of course, is illegal. Not reporting his income is asking for trouble.
If I understand correctly, you already filed a tax return as married filing jointly, but did not include your husband's income. Is that what you did? If so, you knowingly filed a fraudulent tax return. The simplest way to protect yourself would be to change to filing just for yourself, as married filing separately. If you are lucky, the joint tax return that you filed will be rejected. You can then prepare a new tax return as married filing separately and file it. But I don't think it's likely to be rejected. If the joint return is accepted, you have to file an amended return to change your filing status to married filing separately. You are only allowed to do that up until April 15. But if possible you should wait to file the amended return until the IRS has processed the joint return and you have received any refund.
Of course, another option would be to convince your husband to report his income. You could then amend your joint return to include his income.
