The following rules shall apply to the definition of "married person" in section 43-1001:
1. An individual who is legally separated from his or her spouse under a decree of dissolution of marriage or of separate maintenance shall not be considered as married.
2. A taxpayer shall be considered as married at the close of the taxable year if his or her spouse died during the taxable year and the taxpayer would have been considered married at the date of the death of such spouse.