The associates of public figures must not even be suspected of wrongdoing. (The ancient Roman Julius Caesar is supposed to have said this when asked why he divorced his wife, Pompeia. Because she was suspected of some wrongdoing, he could not associate with her anymore.) Jill: I don't think the mayor is trustworthy; his brother was charged with embezzlement. Jane: But the charges were never proved. Jill: That doesn't matter. Caesar's wife must be above suspicion. When the newspapers reported the rumor that the lieutenant governor had failed to pay his taxes, the governor forced him to resign, saying, "Caesar's wife must be above suspicion."
This expression referred originally to Caesar's second wife Pompeia. According to rumours circulating in about 62BC, it seems that her name was linked with Publius Clodius, a notorious dissolute man of the time. Caesar did not believe such rumours but he made it clear, when divorcing her, that even Caesar's wife must be above suspicion. The expression like Caesar's wife also comes from this account, to refer to someone who is pure and honest in morals.