John Gill Commentary Romans 7:2

"For the woman that hath a husband is bound by law to the husband while he liveth; but if the husband die, she is discharged from the law of the husband." — Romans 7:2 (ASV)

For the woman which has an husband
The former general rule is here illustrated by a particular instance and example in the law of marriage; a woman that is married to a man,

is bound by the law to her husband ;
to live with him, in subjection and obedience to him,

so long as he lives ;
except in the cases of adultery, (Matthew 19:9) , and desertion, (1 Corinthians 7:15) , by which the bond of marriage is loosed, and for which a divorce or separation may be made, which are equal to death:

but if the husband be dead, she is loosed from the law of her
husband ;
the bond of marriage is dissolved, the law of it is abolished, and she is at entire liberty to marry whom she will, (1 Corinthians 7:39) .