You cannot file Head of Household if you and your wife live together. You can, however, amend your return to change your filing status to Married Filing Separately. However, in your situation, since you have already filed your return, a better option would be to file an "Injured Spouse" claim (Form 8379). The following explains about Injured Spouse Allocation how to proceed (be sure to read the instructions for What if I've already filed my tax return?).