Since your returns have been filed as Married Filing Jointly you should use her account. You do not need another account.
Additionally, if you are legally married and living together you can only file your tax return as either Married Filing Jointly or Married Filing Separately.
Head of Household as a filing status can only be used if you are Single or you are married and have not lived with your spouse at any time during the last six months of the year. Additionally. the Standard Deduction for MFJ is much higher than HOH.
