Romans 7:2-3

7:2 For a married woman is bound by law to her husband as long as he lives, but if her husband dies, she is released from the law of the marriage. 7:3 So then, if she is joined to another man while her husband is alive, she will be called an adulteress. But if her husband dies, she is free from that law, and if she is joined to another man, she is not an adulteress.