Bibliography: leaves 235-261 / Queer studies have not adequately considered gay men seeking sexual exclusivity within longterm relationships. In contrast, the emphasis has been on understanding evolving queer norms. Homonormativity has been informing sexual permissiveness. In accordance, and contrasting gay men seeking sexual exclusivity, gay, male couples tended to use relationship agreements to stipulate guidelines for extradyadic sex. This study was inspired by my inability—as a counsellor of gay men seeking sexual exclusivity—to provide them with credible insights to better understand their goals. Representing an initial step in generating practical knowledge, it was anticipated that my counselling clients could benefit from an exploration of lived experiences rather than having to rely on theoretical inferences and opinions. “How” and “why” participants maintained sexual exclusivity were the main targets of discovery. Eleven gay, Canadian men aged thirty-three and older, in relationships of five years or longer, participated in semistructured interviews in-person or via video chat. Using Kleiman’s (2004) protocol for phenomenological analysis, common units of meaning were coded, from interview responses, so that distinct subthemes, contributing to six themes, were identified. These findings included content concerning “seeking positive affects,” “avoiding negative affects,” “factors supporting sexual exclusivity,” “threats to sexual exclusivity,” “rigidity in beliefs,” and “decision-making toward sexual exclusivity.” The first two themes integrated innately to form a meta-theme, “emotional optimization.” An essential insight into how participants maintained sexual exclusivity was their awareness of, and restraint in using, sexually tantalizing, visual stimuli, which was the primary risk to sexual exclusivity. Suggestions for gay men desiring sexual exclusivity included discontinued utility of pornography and cybersex. Varied implications for prospective research, clinical practice and support groups were delineated. / Psychology / D. Phil. (Psychology)