"You have heard that it was said, 'You shall not commit adultery.' But I say to you that every one who looks at a woman lustfully has already committed adultery with her in his heart."
 

  "Nothing outside a man can make him 'unclean' by going into him. Rather, it is what comes out of a man that makes him 'unclean.'" (Mark 7:15-16)

"'Love is the fundamental and innate vocation of every human being' By creating the human being man and woman, God gives personal dignity equally to the one and the other. Each of them, man and woman, should acknowledge and accept his sexual identity. Christ is the model of chastity. Every baptized person is called to lead a chaste life, each according to his particular state of life. Chastity means the integration of sexuality within the person. It includes an apprenticeship in self-mastery. Among the sins gravely contrary to chastity are fornication, pornography, and homosexual practices. The covenant which spouses have freely entered into entails faithful love. It imposes on them the obligation to keep their marriage indissoluble. Fecundity is a good, a gift and an end of marriage. By giving life, spouses participate in God's fatherhood. The regulation of births represents one of the aspects of responsible fatherhood and motherhood. Legitimate intentions on the part of the spouse do not justify recourse to morally unacceptable means (for example, direct sterilization or contraception). Adultery, divorce, polygamy and free union are grave offences against the dignity of marriage."
 

  ""But at the beginning of creation God 'made them male and female.' 'For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh.' So they are no longer two, but one. Therefore what God has joined together, let man not separate." When they were in the house again, the disciples asked Jesus about this. He answered, 'Anyone who divorces his wife and marries another woman commits adultery against her. And if she divorces her husband and marries another man, she commits adultery."" (Mark 10:6-12)