Introducing a novel sexual behaviour into an existing relationship may help to improve relationship quality and potentially re-ignite feelings of passion and improve intimacy. A new sexual behaviour introduced into a couple’s longstanding romantic relationship can constitute a shared, novel, exciting, and pleasurable activity, and such experiences may alleviate relationship boredom and improve partners’ feelings for one-another and their relationship. Further, shared novel sexual activities provide an opportunity to learn new things about a partner, and may act as a catalyst for the self-disclosure of privately held thoughts, feelings and preferences, which will deepen intimacy and bolster passion between partners. Finally, novel sexual behaviours that improve the frequency, quality, and timing of coital orgasm, within the romantic relationship may have intrinsically positive effects on sexual satisfaction in both partners in and of themselves. This study will examine the impact of novel sexual behaviours on relationship quality by asking heterosexual couples to engage in shared use of a novel vibrator while engaging in novel sexual positions, or engage in novel sexual positions without an accompanying vibrator, and compare changes in their feelings of intimacy, passion, sexual satisfaction and relationship satisfaction, to a group of couples who will not be asked to modify their sexual behavior.