you'll need to include form 8379 injured spouse allocation. however, there is no way for us to determine if this is better than married filing separately. basically, taxes are prorated based on each taxpayer's taxable income. certain credits are applied. some are based on the taxpayer that earned them others based on income. then there additional taxes such as SE tax which is specific to each taxpayer and a tax like alternative minimum tax would likely be prorated. each taxpayer gets credits for their withholding and any tax payments such as estimated tax need to be allocated by the taxpayer.
