Neb. Rev. Stat. § 28-701

(1) If any married person, having a husband or wife living, shall marry any other person, he shall be deemed guilty of bigamy, unless as an affirmative defense it appears that at the time of the subsequent marriage: (a) The accused reasonably believes that the prior spouse is dead; or (b) The prior spouse had been continually absent for a period of five years during which the accused did not know the prior spouse to be alive; or (c) The accused reasonably believed that he was legally eligible to remarry. (2) Any unmarried person who knowingly marries a person who is married commits bigamy. (3) Bigamy is a Class I misdemeanor.