The previous post did a nice job in articulating Emma's condition. I would merely add that much of the disillusionment in Emma's life comes from being crushed by the weight of her own dreams. Emma is an irrepressible dreamer. She believes in the sincerity of her dreams, almost so that her entire consciousness is contingent upon them. Her dreams of love, of financial success, of social acceptance, of personal betterment are what drive her and her state of being. When these become fruitless, they show how Flaubert carved a conception of dreams, as elements that can animate human consciousness but also cause intense pain and hurt within the individual. In the end, these dreams are what ends up withering Emma away, and, afterwards, Charles.
The story described Emma as a woman who became consumed with reading love stories, and with dreaming and fantasizing altogether. As it was custom, she was basically "given" to Dr. Bovary, whom had just widowed and became fixated with her beauty, youth, and politeness.
Yet, this woman he married was in the inside a dreamer. She wanted her life to be like that in the novels she read, and she dreamed on having all that they had: the gilded life, rank in society, shiny things, great things to eat, evening balls, wonderful foods to eat, romances, aristocratic mannerisms, and especially lots and lots of money.
Her disillusions were plenty: Charles Bovary was as plain as he was boring. The country life had nothing in common with the city and cosmopolitan life she desired. She only had money to spend on necessities and no outlet to expand her love for decorations, and for the good life. She felt trapped in that marriage and that was the reason why she ended up plunging herself into a world of fantasy and excess which would eventually lead to her death, and the destruction of Charles's life as he knew it.