Previous research on sexual practices and commitment to monogamy of individuals has primarily been conducted on populations who endorse traditional sexual orientation labels of heterosexual, bisexual, and homosexual. Recent studies, however, demonstrate 16% of men and 37% women demonstrate some form of non-heterosexual attraction, behaviour, or fantasy although they endorse a heterosexual orientation status. The present study explored the impact of attitudes towards monogamy and casual sex for individuals who endorse non-heterosexual impulses but a heterosexual sexual orientation. A sample of 1,614 heterosexual men and women completed a voluntary questionnaire about sexual orientation, attraction, behaviours, and their attitudes towards casual sex and monogamy. Results revealed individuals who reported non-heterosexual sexual impulses endorsed increased acceptance of non-monogamous behaviour and increased acceptance of casual sex. Findings demonstrate the importance of providing education to clients about sexual orientation development, as well as ensuring that mental health providers and researchers alike do not force traditional labels of sexual orientation onto individuals. Furthermore, results indicate counsellors should establish a framework to engage couples and individuals in discussing their desires for casual sex and non-monogamy in an environment which is both accepting and understanding of that person’s experience.