Since you are married as of December 31, you cannot file as Single. You can choose to file as Married Filing Jointly or Married Filing Separately. (You can only file as Head of Household in the rare case where you have been living apart from your spouse for the last 6 months of the year and you have a dependent.)
The way the tax rates are structured, filing as Married Filing Jointly (MFJ) is almost always better than Married Filing Separately (MFS), especially when the two people's incomes are very different. This is because when filing as MFJ, you will basically be taxed on the "average" of the two people's incomes (since the brackets for MFJ are twice the corresponding brackets for MFS), and the tax brackets are progressive, meaning a higher income is taxed at higher rates, so the average is always better or the same compared to the two incomes separately. There are also many other disadvantages for MFS, e.g. the income limits for Traditional IRA deduction and Roth IRA contribution are almost 0.
The only case where MFS might be better than MFJ is if one spouse's lower income qualifies them for some itemized deduction or tax credit that the combined income level in MFJ does not qualify for, and the benefit of this additional deduction exceeds the disadvantage in tax rates.