By the standards of his day, Leonce Pontellier is the perfect husband. This guy makes a good living and is a popular figure in society. He gives Edna plenty of money, indulges her hobbies, and even sends her care packages packed with goodies:
A few days later a box arrived for Mrs. Pontellier from New Orleans. It was from her husband. It was filled with friandises, with luscious and toothsome bits--the finest of fruits, pates, a rare bottle or two, delicious syrups, and bonbons in abundance.
Mrs. Pontellier was always very generous with the contents of such a box; she was quite used to receiving them when away from home. The pates and fruit were brought to the dining-room; the bonbons were passed around. And the ladies, selecting with dainty and discriminating fingers and a little greedily, all declared that Mr. Pontellier was the best husband in the world. Mrs. Pontellier was forced to admit that she knew of none better. (3.18-19)
So, um, what’s the problem?
Well, to start with, he acts like Edna is his property. Mr. Pontellier certainly treats Edna well, but in the same way that you treat your dog well. You pamper it and give it treats, but at the end of the day, you expect it to behave and turn tricks.
"You are burnt beyond recognition," he added, looking at his wife as one looks at a valuable piece of personal property which has suffered some damage. (1.11)
The sex in their marriage also isn’t very inspiring. Edna’s first kiss with Alcee Arobin, a man she doesn’t love (or even really like all that much) was "the first kiss of her life to which her nature had really responded."
When Edna starts claiming greater independence, Leonce is confused. He adhered to the Perfect Husband mold, and expects a Perfect Wife in return: a woman who takes care of the house, dotes on her children, and keeps up with the social demands that he deems necessary. Bewildered by Edna’s refusal to conform, he becomes convinced that there is something physically wrong with her. In all of these ways, Leonce is illustrative of a man of his time, allowing us to focus on the evolution of Edna’s character.