Bigamy is the offense of being married and knowing that his lawful spouse is living, marries another person or carries on a bigamous cohabitation with another person.
Marrying a bigamist is a related offense can be applicable to a person who marries someone who they know to be currently married.
There is an exception where the spouse has been continually absent for a period of seven years during which time the accused did not know the prior spouse to be alive and the person reasonably believed they were eligible to remarry.
These are felony offenses which carries 1 to 10 years.
From a defense standpoint, the prosecution must prove the fact of the prior marriage.