Neb. Rev. Stat. § 42-374: Neb. Rev. Stat. § 42-374

A marriage may be annulled for any of the following causes:

(1) The marriage between the parties is prohibited by law;

(2) Either party is impotent at the time of marriage;

(3) Either party had a spouse living at the time of marriage; or

(4) Force or fraud.