In Sense and Sensibility Austen contrasts two sisters and their very different styles of courtship- one, Marianne- all emotion, the other, Elinor- all common sense and decorum. Since this Austen novel is paired with a focus on Allegra who is meteoric, passionate, emotional, and self centred we are encouraged to compare her to Marianne ( who is a secondary character in S&S).
In S&S Marianne falls head over heels for the gallant and adventurous Willoughby. He turns out to be a rat...well, perhaps not a rat, but while he "courted" Marianne when it came down to the crunch other virtues ( wealth, position) had more weight. Marianne, in her depression at Willoughby's betrayal goes out in the rain and becomes ill [but recovers]
Allegra is lesbian and her lover Corinne appears at first as adventurous and impulsive as Allegra but turns out not to be as she seems, we are told. Corinne betrays Allegra; Allegra tells Corinne secrets, stories and Corinne steals them and tries to sell them and fails. [It is speculated that Austen was lesbian as she never married and of course writes stories, and her early manuscripts were rejected.] Allegra discovers Corinne's betrayal. " How dare Corinne write up Allegra's secret stories and send them off to magazines to be published? How dare Corinne write them so poorly that no one wished to take them?"
She leaves in the rain in only a T shirt , drives to her parents and stays in bed for 3 days (compare to Marianne's outing in the rain in S&S) There are secrets revealed in S&S too. Elinor's love interest Edward is secretly attached to Lucy but this secret is revealed by Lucy's sister causing much upset in vaious quarters. In the end though Lucy succumbs to the lure of wealth also and accepts the "better" offer of brother Robert instead, leaving Edward conveniently for Elinor. But what about Marianne? She ends up with Col. Brandon, a nice older man, who cares for her. And what will happen to Allegra? If she leaves Corinne for good who will she end up with.
Fowler in the Austen Book Club is taking situations from not the Austen's main character but secondary ones. "It wasn't Jane Austen's fault that love went bad. You couldn't even say she didn't warn you. Her heroines made out well enough but there were always other characters in the book who didn't finish happily...These were the women to whom you should be paying attention, but you weren't"