Buddy Willard is Esther's not-so-smooth sort-of-boyfriend. He's the kind of guy that, if you're a guy, your mother is always trying to get you to be more like him. And if you're a girl, he's the kind of guy that your mother is always trying to set you up with because he's her idea of perfection. No matter how cool said guy is, you know there has to be something terribly wrong with him to make your mother adore him to pieces.
Buddy is that guy, and then some. The son of Esther's mother's friend, Buddy is the big guy on campus when Esther meets him in high school. They start dating while he's at Yale, and continue when he enters medical school (can't you see your mother swooning?). Get this – they make out behind the chemistry lab at Yale. At this point, your mom is probably drawing up the wedding invitations.
Of course, Buddy is what we could call nowadays a tool. While he looks great on paper, Buddy's interactions with Esther reveal him to be at times callous, oblivious, and just plain pathetic. Buddy is constantly making Esther feel irrational and ignorant in contrast to his supposedly superior, logical, scientific self. When Buddy undresses in front of Esther, and Esther compares his, um, meat-and-potatoes matter-of-factly to turkey guts, it's hard not to feel that Buddy sort of deserves to be ridiculed.
And Buddy gets the unenviable job of being the vehicle for male chauvinism in the novel. The novel takes a whack at sexism by showing how Buddy's sense of masculine superiority is built on moral hypocrisy. Buddy is unable to respect Esther's literary aspirations, nor does he have any inkling about her sexual desires, although he takes his own for granted as we see in his sexual affair with the waitress on Cape Cod. He seems to view Esther mainly as someone who is destined to be his wife and the mother of his children.
But let's not be so hard on Buddy. The novel sticks him in a tuberculosis sanatorium for a while, and then not only Esther, but also his former flame Joan attempt suicide. With Joan's death, we see another, more fragile Buddy, without the self-serving sheen from earlier in the novel. This unexpectedly sympathetic side of Buddy is one of the few redeeming images of men we get in The Bell Jar.