A married couple always has the option of filing separately. To file jointly, both must agree to it. However, it is usually not advantageous.
Although there is no
one answer since every situation is different, generally filing jointly will
give you a bigger refund or less taxes due. When you file separately, your tax
rate is higher and you won't be able to claim:
On top of that, if you live in the
community property states of Arizona, California, Idaho, Louisiana, Nevada, New
Mexico, Texas, Washington, or Wisconsin, you have to deal with community property allocations and adjustments, which adds extra work and complexity
to your tax preparation chores.
Tip: Only taxpayers who were still legally married as
of December 31, 2017 are able to file as marrieds, whether jointly or
separately.