Rules theory is the framework for this study's analysis of ordinary language contained in break-up accounts. It attempts to understand the relationship expectations which parties have for their opposite-sex romantic relationships. Break-up accounts from 157 respondents produced eight primary reasons/rules relevant to this relationship type: the obligation to grant autonomy beyond the relationship; the expectation of similarity; the obligations to be supportive, loyal and open; the expectation of shared time between relationship parties; the expectation of equity; and the expectation that a romantic relationship will be characterized by an inexplicable `magic' quality. Females were significantly more likely to mention autonomy, openness, and equity reasons in their break-up accounts than males were; males, in turn, more frequently mentioned the lack of the magical quality as a reason for break-up. Overall, females mentioned significantly more reasons/rules for break-up than did the male respondents in the sample.