Mark 10:11
And He said to them, "Whoever divorces his wife and marries another [woman] commits sexual unfaithfulness [toward her].
Luke 16:18
"Every person who divorces his wife and marries another woman becomes sexually unfaithful to her [i.e., because he is still regarded by God as married to his first wife. See Matt. 19:9]. And the person who marries someone who has been divorced by her husband commits sexual sin with her [i.e., because she is still rightfully married to her first husband].
Matthew 5:31-32
It was also said [Deut. 24:1-3], 'Whoever divorces his wife, let it be done with a [legally binding] divorce decree, which he must give her.'
Matthew 19:9
And I tell you, whoever divorces his wife and marries another woman commits sexual unfaithfulness [toward her], unless the reason for the divorce was sexual unfaithfulness [on his wife's part]. And the person who marries a woman who has been divorced commits sexual sin with her [i.e., because she is still rightfully married to her first husband]."
Romans 7:3
So, if she lives with another man while her husband is still alive, she will be called an adulteress [i.e., a person who is sexually unfaithful to their mate]. But if her husband dies, she is legally free to marry another man without committing adultery.
1 Corinthians 7:4
The wife does not have [sole] authority over her own [physical] body, but the husband [also has his right to it]. And in the same way, the husband also does not have [sole] authority over his own [physical] body, but the wife [i.e., has her right to it, as well].
1 Corinthians 7:10-11
Now I command married people, although it is [really] the Lord's command [See. Mark 10:2-12]: A wife should not separate from her husband. [Note: This act implies the intention of pursuing a legal and permanent breach of the marriage relationship by divorce. "Separate" and "divorce" appear to be used interchangeably in this section. See verses 11-15].
Hebrews 13:4
Marriage should be considered honorable among all people and its sexual responsibilities should be faithfully kept. For God will judge [and condemn] those people who are sexually immoral and who are sexually unfaithful to their mates.