Committing adultery, which includes cheating on one's spouse, is considered a grave offense against the dignity of marriage according to Catholic teaching 1. Adultery is condemned by the sixth commandment and the New Testament, forbidding it absolutely 2. Adultery is seen as an injustice that violates the commitment made in marriage, harms the spouse, undermines the institution of marriage, and affects the well-being of children 3. The Catechism of the Council of Trent emphasizes that adultery defiles the marriage bed and is a serious transgression 4. Therefore, cheating on one's spouse is not considered acceptable within the teachings of the Catholic Church.