In Plath's "The Bell Jar," how do gender double standards in the areas of education/career and sex/marriage contribute to Esther's mental breakdown?

As we read the story, we come to realize that Esther is experiencing an adolescent crisis of identity, similar to what many teenagers of her age experience. Although gender double standards play a part in Esther's breakdown, it is mainly Esther's inability to reconcile these differences that fuel her descent into madness.
Esther's boyfriend, Buddy Willard, has asked her to marry him. For her part, Esther is non-committal; she believes that Buddy is a hypocrite because he's had an affair with a waitress. It upsets her that a woman is expected to retain her virginity before marriage, while a man is free to satiate his sexual appetite. Buddy's mother is also obsessed with the topic of virginity; however, she expects all marriageable young adults to maintain their purity until marriage. Mrs. Willard also rejects the idea of sexual compatibility being an integral part of one's decision to marry. As a result, Buddy is husband material from a fiscal standpoint but a failure in the romance department. Esther is fascinated by Buddy's academic achievements but repelled by his lack of sexual experience.
Thus, Esther's descent into madness is fueled by her inability to reconcile divergent points of view about male and female sexuality. First, there is the larger societal expectation for young men to fulfill the dictates of their sexual appetites before marriage. Second, there is the orthodox belief that all young adults should maintain sexual purity until the marriage ceremony is performed. Third, there is the youthful feminine inclination to desire more than financial security from marriage. For her part, Esther is drawn towards poetry because her soul is starving for true affection and purpose. Her depression and anxiety are fueled by the conflicting gender double standards that vie for her attention.
Sadly, Buddy is powerless to provide Esther what she seeks because he has little understanding of the female psyche himself. His appreciation of the birth experience is clinical at best, and he nurses grave misconceptions about female sexuality. He sees Esther as a means to an end. Buddy knows that he has to marry in order to fulfill his masculine obligations to society, but he has little knowledge about what fuels a woman's admiration and respect for a man.
Buddy believes that he can give Esther financial security and is genuinely perplexed that Esther displays so little enthusiasm for his efforts. He tries to understand Esther's devotion to poetry and humors her. However, he is hardly supportive of it. Consider that Buddy isn't just being insensitive: he's as much at a loss as Esther is. The gender double standards that encompass their lives provide very little guidance about sexual attraction, compatibility, and devotion within a marital union.
For Esther, poetry is a lifeline. She is secretly terrified at the idea of marriage. With few domestic skills, Esther believes that she would fail miserably in any domestic role. She seeks personal fulfillment but has few emotional resources to determine the most important priorities in her life. 

From the tip of every branch, like a fat purple fig, a wonderful future beckoned and winked. One fig was a husband and a happy home and children, and another fig was a famous poet...another fig was Constantin and Socrates and Attila and a pack of other lovers with queer names and offbeat professions...and beyond and above these figs were many more figs I couldn't quite make out. I saw myself sitting in the crotch of this fig tree, starving to death, just because I couldn't make up my mind which of the figs I would choose. I wanted each and every one of them, but choosing one meant losing all the rest...

The above passage clearly explains how conflicting double standards fuel Esther's descent into madness. The standards provide a sterilized, monochromatic blueprint for life, but they fail to provide practical solutions for individual concerns. With little purpose in life, Esther finds personal fulfillment elusive. Tragically, she never learns that it is possible to combine the "figs" of her desires into a workable union of interests.