How we cite our quotes:
As she stepped outside, Alcée Laballière rode in at the gate. She had not seen him very often since her marriage, and never alone. (2.2)
This tells us a great deal about marriage and society at the time the story is set: it wouldn't be proper for former lovers to hang out much once they'd both married other people. It also shows how intense Calixta and Alcée's relationship must have been. Why else would they avoid each other so assiduously after parting and still feel so strongly for each other five years later?
Then, prepared for the worst – the meeting with an over-scrupulous housewife, they entered cautiously at the back door. (3.1)
Bobinôt thinks "the worst" thing that awaits him is "an over-scrupulous housewife" who's angry about a little mud. This is kind of ironic, considering that something far worse for his marriage just took place under his own roof. Poor Bobinôt. After the afternoon Calixta's had, mud is probably the last thing on her mind.
Bobinôt's explanations and apologies which he had been composing all along the way, died on his lips as Calixta felt him to see if he were dry, and seemed to express nothing but satisfaction at their safe return. (3.5)
It's ironic that Bobinôt has been working so hard to come up with "explanations and apologies" for his actions. Actions like keeping their son safe during the storm, rushing home as soon as possible, and bringing home his wife's favorite food. Obviously it's Calixta, not Bobinôt, who has something to apologize for. But she seems more worried about Bobinôt and Bibi than what she did with Alcée.