If the taxpayer and spouse are both non-residents, and the taxpayer is the only one with Deleware source income, is the spouses still required to fill a Delaware married filing separate return? The filing status is Married filing separate returns.
Only the taxpayer with De income has to file. Depending on the spouse's income, it may help to file jointly.
If the spouse with no De income has very little income, then maybe file them jointly. If income is equal usually filing separate is more advantageous. You can file separately in ProSeries, but you get error messages. In that case do not efile.