You can always file a joint return if you agree to. If you are living in separate states, it is usually allowed to file a joint federal return and separate state returns, to avoid having each spouse's income taxed in the state where they don't live. This is a little more complicated than a regular tax return, if you want help with this, let us know and tell us which states. If you file a joint federal return, you don't to worry about the special rules and limitations for married filing separately.
However, if you decide to file separate federal and state returns, then you must both itemize if one itemizes, even if you don't have enough deductions. That's how Congress wrote the law.
