Ohio Rev. Code § 2919.01: Bigamy.

(A) No married person shall marry another or continue to cohabit with such other person in this state.

(B) It is an affirmative defense to a charge under this section that the actor's spouse was continuously absent for five years immediately preceding the purported subsequent marriage, and was not known by the actor to be alive within that time.

(C) Whoever violates this section is guilty of bigamy, a misdemeanor of the first degree.