chunk: When Mrs. Cheveley pointedly informs Lady Chiltern of Sir Robert's change of heart regarding the canal scheme, the morally inflexible Lady Chiltern, unaware of both her husband's past and the blackmail plot, insists that Sir Robert renege on his promise. For Lady Chiltern, their marriage is predicated on her having an "ideal husband"âthat is, a model spouse in both private and public life that she can worship: thus Sir Robert must remain unimpeachable in all his decisions. Sir Robert complies with the lady's wishes and apparently seals his doom. Also toward the end of ActÂ I, Mabel and Lord Goring come upon a diamond brooch that Lord Goring gave someone many years ago. Goring takes the brooch and asks that Mabel inform him if anyone comes to retrieve it.