Romans 7:2-3

2For the woman who has a husband is bound by the law to her husband as long as he lives. But if the husband dies, she is released from the law of her husband.

3So then if, while her husband lives, she marries another man, she will be called an adulteress; but if her husband dies, she is free from that law, so that she is no adulteress, though she has married another man.