Final answer:
The reason why Monsieur de Villefort was not at the party with his wife is not specified in the provided texts. Other characters in the texts make personal choices about attending social events based on family considerations or emotional entanglements, hinting at possible motivations for absences from such gatherings.
Step-by-step explanation:
The character Monsieur de Villefort is not mentioned in the provided texts, thus it cannot be determined why he was not at the party with his wife. However, another character, Alcée Laballière, wrote a loving letter to his wife Clarisse, suggesting he would not attend because he was content to remain apart while they enjoyed their time in Biloxi for the sake of their health and pleasure.
Alcée's considerate nature might imply that if Monsieur de Villefort were in a similar situation, his reasons might be equally thoughtful and considerate.
The materials given focus on various characters from different stories and their respective situations concerning social events and family matters. In "At The 'Cadian Ball," for instance, we learn about Bobinôt's conflict over attending a ball where he might encounter Calixta, a woman he feels strongly about despite the complications she brings to his life.
These narratives provide context for the social dynamics and personal choices characters make, which could be extrapolated to imagine why someone like Monsieur de Villefort might not attend a party.