People spend a considerable amount of time thinking about their future. When doing so they likely anticipate a wide variety of outcomes; some positive, some negative. Past research suggests anticipating both positive and negative outcomes (termed a ‘realistic orientation’) is more adaptive than simply considering positive outcomes (termed a ‘positive orientation’) as the individual should be less blindsided if setbacks occur. This thesis examined whether a realistic orientation would be protective against unexpected challenges and unmet expectations during a time of transition for romantic partners (i.e., cohabitation). In Studies 1 (n = 86) and 2 (n = 79), individuals who were in a romantic relationship were invited to complete an orientation to cohabitation scale as well as scales measuring defensive pessimism, hope, and optimism (in Study II only). Results showed that the orientation to cohabitation scale had good reliability and discriminant validity. In Study 3, individuals who were in a romantic relationship and planning on moving in with their partner for the first time were invited to participate. Study III had three waves of data collection: four to eight weeks prior to moving in together (n = 290); 12 weeks after moving in together (n = 176); and 24 weeks after moving in together (n = 171). The data were analyzed using hierarchical linear modelling. The results showed that (a) orientation did not buffer the negative effects of unmet expectations. When expectations were unmet relationship satisfaction decreased over time for both positively and realistically oriented participants; (b) when expectations were met realistically oriented participants reported an increase in commitment where positively oriented participants did not; (c) unexpected challenges did not influence relationship satisfaction or commitment. The findings suggest unmet expectations can negatively influence relationship satisfaction over time, regardless of orientation. Additionally, the findings suggest that a realistic orientation is as adaptive as a positive orientation. It appears that considering negative possibilities is not necessarily harmful for one’s relationship.