Irigaray's early work seeks to multiply possibilities for women's self-expression by recovering a sexual difference in which male and female are neither the same nor opposites, but irreducibly different modes of embodiment. In her more recent work, however, Irigaray has emphasized the duality of the sexes at the expense of multiplicity, enshrining the heterosexual couple as the model of sexual ethics. Alison Stone's recent revision of Irigaray supplements her account of sexual duality with a theory of bodily multiplicity derived from Butler, Nietzsche, and certain German Romantics; but to the extent that Stone maintains the primacy of sexual duality, her revision fails to address the claims of multiplicity on their own terms. In this paper, I interpret a passage from Marcel Proust's novel, Sodom and Gomorrah, in order to develop an alternative theory of sexual difference in which sexual duality is affirmed in relation to a third, unsexed but sexual force which multiplies the possibilities for sexual pleasure beyond heterosexual coupling. Proust's emphasis on sexed ``parts'' rather than sexed morphologies is generative of maximally diverse combinations, all of which are equally natural and equally enhanced through artifice.