If your divorce is not final you file Married Filing Separately. Below are the basic rules for Married Filing Separately.
See IRS Publication 504 for more information:
Married Filing Separately
If
you and your spouse file separate returns, you should each report only
your own income, exemptions, deductions, and credits
on your individual return. You can file a
separate return even if only one of you had income. For information on
exemptions
you can claim on your separate return, see Exemptions, later.
Community or separate income.
If you live in a community property
state and file a separate return, your income may be separate income or
community
income for income tax purposes. For more
information, see
Community Income
... under
Community Property, later.
Separate liability.
If you and your spouse file separately,
you each are responsible only for the tax due on your own return.
Itemized deductions.
If you and your spouse file separate
returns and one of you itemizes deductions, the other spouse can’t use
the standard
deduction and should also itemize deductions.
