Romans 7:3

So then, she will be called an adulteress if she lives with another man while her husband is alive. But if her husband dies, she is free from that law, and though she marries another man, she is not an adulteress.

Matthew 5:32

But I say to you that every one who divorces his wife, except on the ground of unchastity, causes her to become an adulteress; and whoever marries a divorced woman commits adultery.

Mark 10:6-12

But from the beginning of creation God 'made them male and female.'

John 8:3-5

Then the scribes and the Pharisees brought to him a woman caught in adultery. And when they had set her in the midst,

1 Timothy 5:11-14

But refuse to put younger widows on the list, for when they feel sensual desires in disregard of Christ, they want to marry,

Treasury of Scripture Knowledge

Summary

So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man.

General references

Bible References

So then

Matthew 5:32
But I say to you that every one who divorces his wife, except on the ground of unchastity, causes her to become an adulteress; and whoever marries a divorced woman commits adultery.
Mark 10:6
But from the beginning of creation God 'made them male and female.'
John 8:3
Then the scribes and the Pharisees brought to him a woman caught in adultery. And when they had set her in the midst,

Though

1 Timothy 5:11
But refuse to put younger widows on the list, for when they feel sensual desires in disregard of Christ, they want to marry,

General references

Mark 10:9
Therefore what God has joined together, let not man separate."