A wife is bound by the law of marriage to her husband as long as he lives. If her husband dies, she is then free to marry whomever she desires, but only to one who belongs to our Honored Chief.
So if she gives herself to another man while her husband lives, she will be guilty of unfaithfulness to her husband. But if her husband is no longer alive, she would not be guilty of unfaithfulness. His death has released her from the law of marriage.
But now that we have died, we have been released from the law that kept us bound. We now walk in the new way of the Spirit, and not in the old way of a law carved in stone and written with ink on paper.