CCC 2380

Adultery refers to marital infidelity. When two partners, of whom at least one is married to another party, have sexual relations - even transient ones - they commit adultery. Christ condemns even adultery of mere desire.¹⁷⁰ Cf. Mt 5:27-28. The sixth commandment and the New Testament forbid adultery absolutely.¹⁷¹ Cf. Mt 5:32; 19:6; Mk 10:11; 1 Cor 6:9-10. The prophets denounce the gravity of adultery; they see it as an image of the sin of idolatry.¹⁷² Cf. Hos 2:7; Jer 5:7; 13:27.