My wife and I have been legally separated since 2016 and we have lived apart during that entire time. I have been paying marital maintenance (alimony) to the tune of over $20K for the entirety of 2017. I naturally would like to take the tax deduction I am entitled to for this. My separated wife (and lawyer) want us to file jointly since that way she wouldn't have to pay the income tax on that maintenance.
Is there something in the tax code that addresses whether a couple that has been living separately has to file as married, filing separately? How else can I get to claim this tax deduction?
First, as long as you are legally married, the IRS considers you to be married, so you can't file single or Head of Household. And unfortunately, any payments you made to support your spouse before the divorce is final are not considered alimony by the IRS unless they are pursuant to a court order and specified as alimony.
Second, married taxpayers have the option to file jointly or separately. There is no rule that forces you to file either way. But filing separately usually results in higher income and higher taxes.
See these two articles for more on this topic: