Iowa Code § 726.1: Bigamy.

1. a. Any person, having a living husband or wife, who marries another, commits bigamy.

b. Any person who marries another who the person knows has another living husband or wife commits bigamy.

2. Bigamy is a serious misdemeanor.

3. Any of the following is a defense to the charge of bigamy:

a. The prior marriage was terminated in accordance with applicable law, or the person reasonably believes on reasonably convincing evidence that the prior marriage was so terminated.

b. The person believes, on reasonably convincing evidence, that the prior spouse is dead.

c. The person has, for three years, had no evidence by which the person can reasonably believe that the prior spouse is alive.