In the romance novels published by Harlequin Mills & Boon, sex and love are inextricably intertwined. The governing paradigm of the romance is a concept I have termed 'compulsory demisexuality'. Someone who is demisexual only experiences sexual attraction to someone with whom they have an emotional bond. In the romance, this means that sex is only truly pleasurable when the partners are in love. The intersection of this paradigm with the notion of one true love means that the romance hero and heroine can only find real sexual pleasure with the other. This paradigm manifests differently between genders. Generally, heroines are demisexual, whereas heroes become demisexual. This change wrought in the hero is the key to understanding the romance text as a text of feminine victory: the ubiquitous happily-ever-after of the romance takes place in the heroine's world. The way in which compulsory demisexuality has been realized within category romances has also changed over time. This article will discuss the historical evolution of the gendered relationship between sex and love in relation to two key texts, Denise Robins's Shatter the Sky (1933) and Lynne Graham's Desert Prince, Bride of Innocence (2009), focusing particularly on how the heroine's sexual desire has complicated this relationship.