The Seventh Commandment

Yahweh desired that the Hebrews be monogomous and sexually faithful to their maried partner. Since the sacrament of marriage is a divinely sanctioned union meant to serve a the basis for holding society together, and bringing children forth to perpetuate the species, that union is not to be tarnished and belittled by adulterers unfaithful to their vows of mariage. The message is clear--be faithful to your partner.