Mark 10:10 And in the house his disciples asked him again of the same matter.
Mark 10:11 And he saith unto them, Whosoever shall put away his wife, and marry another, committeth adultery against her.
Pretty simple answer.
Mark 10:12 And if a woman shall put away her husband, and be married to another, she committeth adultery.
Is there no offense that is not legal grounds for divorce?
Mat 5:32 But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery.
fornication: adultery denotes one "who has unlawful intercourse with the spouse of another," A man who indulges in unlawful sexual intercourse, a fornicator, from the Greek word: pornos Indulging in lusts as from pornography, unclean behavior.
Mat 5:28 But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.
1 Pet 1:13 Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ;
1 Pet 1:14 As obedient children, not fashioning yourselves according to the former lusts in your ignorance:
1 Pet 1:15 But as he which hath called you is holy, so be ye holy in all manner of conversation;
1 Pet 1:16 Because it is written, Be ye holy; for I am holy.
A Christian has the Holy Spirit within, to keep him or her from adultery. We do not follow the ungodly ways of the world.
Seek forgiveness and the grace of Jesus and sin no more.