Why is Edna's husband upset in Chapter 3?

Mr. Pontellier is upset because is wife is sleeping and unaware that their son is running a fever.

Mr. Pontellier returned to his wife with the information that Raoul had a high fever and needed looking after. Then he lit a cigar and went and sat near the open door to smoke it.

Mrs. Pontellier was quite sure Raoul had no fever. He had gone to bed perfectly well, she said, and nothing had ailed him all day. Mr. Pontellier was too well acquainted with fever symptoms to be mistaken. He assured her the child was consuming at that moment in the next room.

He reproached his wife with her inattention, her habitual neglect of the children.

It is due to the fact that Mrs. Ponteiller does not act the way how the "normal" wives are supposed to act like. The traditional norm of the wives is to stay home and take an extensive care of the kids and the home, which Mrs. Ponteiller failed to do, so it angered Mr. Ponteiller.