Only Anna Karenina is really about adultery. I mean the Anna strand, pretending the Levin strand doesn’t exist. The novel as a whole, if it’s forgivable to simplistically identify a unifying theme for a something as rich, broad and complex as Anna Karenina, is about the search for happiness and the meaning of life, and 2 kinds of love.
Madame Bovary depicts adultery—Emma has not 1 but 2 affairs, but committing adultery is only a conventional way to rise above the conventional. The novel is really a depiction of, and attack on, philistinism. Emma, Rodolphe, Leon and Homais are all philistines.
Effi Briest isn’t really about adultery either. There’s hardly an affair, even. Fontane’s decision to keep it to a minimum might be an artistic choice to leave everything to the reader’s imagination, or a personal evasion of a difficult task, but now I start to think that by making it subtle to the point of being easily missed, Fontane wants to stress that it’s a minor thing, insignificant and devoid of meaning, nothing to dwell upon, and thus, Innstetten’s overreaction to the discovery appears ridiculous and even laughable, if it were not so tragic.
Effi Briest is more about the bad marriage (how ill-suited Innstetten and Effi are, especially considering that he used to be in love with her mother, which is rather creepy), and about society and the absurd ideas about morality and honour.
“… Flaubert’s title Madame Bovary suggests that the problem, the central concern is the marriage, the turning of Emma into the wife of someone whose bovine name proclaims his character. The marriage fails to satisfy her, but equally she fails to assert a separate valid identity as Emma. Tolstoy’s Anna Karenina articulates the conflict inherent in the simultaneous existence of the private individual Anna, who experiences true love and passion, and the social role as Karenin’s wife. Effi Briest is quite another matter. Effi’s problem is that she cannot complete the socially required metamorphosis from Fraulein von Briest to Frau von Innstetten, for this would entail a denial of her self, her natural, playful exuberance, the self-confident magnetic personality we see in the games in the garden on the 1 hand, and on the other her risk-loving nature, the propensity to let herself be carried away, her desire for the out of the ordinary, her unpredictability. As her mother says, she is ‘altogether a very odd mixture’. That she remains Effi Briest at the end of the noel, a fact explicitly asserted by her instructions for the wording on her gravestone, is a sign that although she has succumbed physically in the draining conflict with the rigid forms of society she has managed to hold on to her own inner integrity, she has not lost her self. She has not been sacrificed like Anna to a grand passion. Her affair with Crampas was not a crucial emotional experience, it was merely a symptom of her need to preserve some area of freedom and spontaneity; nor has she been sacrificed like Emma to romantic notions and an egocentric personality. She has been sacrificed—and the motif of sacrifice runs through the narrative from the gooseberry skins’ watery grave at the beginning to the sacrificial stones by Lake Hertha and beyond (Chapter 24)—to a set of conventions which Wullersdorf and Innstetten recognize as empty ‘this cult of honour of ours is idolatry’, without being able to extricate themselves from the power of ‘that social something which tyrannizes us’ (Chapter 27), but she has not relinquished her irreducible sense of her own independent identity. That she finds her way back to being Effi Briest—a unique, beautiful name free of its aristocratic ‘von’, its social indicator, in her chosen, natural setting in the garden of her youth is an assertion of a triumph of a kind. It is an ambiguous one, for she has not survived to grow into mature adulthood, but the fact of her death constitutes an accusation levelled at a society whose warped logic it has exposed.”
Effi Briest is, in some ways, closer to Madame Bovary than to Anna Karenina. Stylistically, like Flaubert, Fontane stands outside and describes happenings and actions, like a camera, whereas Tolstoy describes scenes but constantly slips into the character’s mind. Thematically, whilst Anna and Vronsky do love each other, Effi and Emma both suffer from ennui, and in both cases, their affairs aren’t about love.
The chief difference is that Effi is a free spirit and suffers in her marriage with a man who tries to stifle her, whereas Emma mistakes her own sentimentality for a romantic and passionate nature, suffers from delusions, and causes her own downfall.