Even the thought of someone eating a human heart can provoke strong emotions. Naturally, when an author actively incorporates this theme as a literary leitmotiv, it can make quite an impression on the reader - and on other writers. Though the motif is an old one indeed, it is enlightening to take a look at the original adaptations of Boccaccio and of others who may have exercised an influence on our author.
The gruesome French tales above of love and revenge have scenarios very similar to some in the Decameron. The husband punishes both the lover and the wife, ironically giving her what she most desired in a form which destroys her and her lover. Forced by her husband to eat her lover's heart unknowingly, the wife becomes the victim of a secret, transgressive and violent act. What is more, the consumption of food can have inherently sensual overtones and, as a consequence, the motif of the eaten heart at times lends itself to a sexual interpretation. In this light, in could be said that the cuckolded husband reasserts his power over the wife through a perversion of intercourse; the ingestion of the lover's heart represents an extreme degree of degradation insofar as it reflects - though in a violent, deviant fashion - the wife's incorporation of her lover's body into her own.
Upon being discovered, however, this act of eating may take on an aspect of a funerary meal, and the ingestion of one into another's body becomes an occasion for grief and mourning. The woman's reaction changes the husband's intended meaning. Thus the symbolism may be variously interpreted according to the narrative function of the characters involved and, in effect, to the attitude of the narrator whom Boccaccio chooses for the telling of the tale.
(C. Sa.) Milad Doueihi. "The Lure of the Heart." Stanford French Review 14 (Spring-Fall 1990): 51-68; Milad Doueihi. "Cor ne Edito." MLN 108.4 (1993): 696-709; Jacques Le Goff. "Head or heart." Zone 3 (1989): 13-27.