Two Bible stories underscore this power. In both cases, adultery is on the table as a problem or potential problem. Yet in both cases, the offense is less the sex itself and more the betrayal of a role and its attendant duties/expectations.
Joseph & Potiphar's Wife
Joseph refuses Potiphar's wife because of the debt he owes his master.
No one is greater in this house than I am. My master has withheld nothing from me except you, because you are his wife. How then could I do such a wicked thing and sin against God?
David & Everybody
When Nathan, the prophet, confronts David, his accusation--in the form of a parable about a rich man, poor man, and ewe-lamb--is a condemnation of David's use of royal privilege at the expense of his citizens. It is one of the most remarkably modern political statements in the Bible regarding power and law.
The viewpoint in Joseph and David's stories is pre-Victorianism. It is pre-oh, no, a woman lost her virginity-men are such dirty dogs!, a state of mind that still resides in our current culture (and for which I blame both the religious right and the progressive, Ivory Tower left).
The offense with Joseph and David is that the act of adultery undermines trust between a man and his servant, a king and his nation. Despite artistic license (see above), in neither case is the woman presented and blamed as some kind of sexual deviant.
Hence, the odd story of Judah in the middle of Joseph's tale: Judah fails to find a husband for his daughter-in-law, who then proceeds to take on the role of a prostitute and seduce him. When the purpose of her act is discovered, the community--which was prepared to stone her--goes, "Oh, okay." Judah is shamed and the matter is closed.
The problem is not the sex. The problem is that he didn't do his job.The New Testament places greater emphasis on the individual's relationship to God but still circles back to the social implications. Jesus speaks to the woman taken in adultery only after he has disposed of her bullies. In addition, Jesus speaks very highly of David whose repentance takes the form of modern-like self-condemnation and pleas for mercy. David repairs his relationship directly with God.
In classical Christianity, back-biting, reviling, pride, one-up-manship, and dog-eat-dog behaviors are consistently considered worse than the physical sins.
To be continued...