If a marriage is void or voidable, a party may obtain a judgment of nullity. A marriage may be void or voidable in circumstances of incest, bigamy, minority, unsound mind, fraud, force or physical incapacity. In order for any one of these circumstances to be grounds for nullity, it must have existed at the time of the marriage. If the circumstance was later eliminated or became known to the party wishing to annul the marriage, and thereafter that party continued to freely cohabitate with the other party as husband and wife, the circumstance may no longer be grounds for nullity.