Matthew 5: 27 - 32
27 "You have heard that it was said, `You shall not commit adultery.'
28 But I say to you that every one who looks at a woman lustfully has already committed adultery with her in his heart.
29 If your right eye causes you to sin, pluck it out and throw it away; it is better that you lose one of your members than that your whole body be thrown into hell.
30 And if your right hand causes you to sin, cut it off and throw it away; it is better that you lose one of your members than that your whole body go into hell.
31 "It was also said, `Whoever divorces his wife, let him give her a certificate of divorce.'
32 But I say to you that every one who divorces his wife, except on the ground of unchastity, makes her an adulteress; and whoever marries a divorced woman commits adultery.

EWTN