In this dissertation, I explored why relational boredom occurs in romantic relationships and how couples can cope with it. Specifically, I proposed shared participation in creative activities as a way to reduce relational boredom and improve relationship quality. Using the self-expansion model as the theoretical framework, I conducted two pilot studies to validate the newly created Partner Appraisal Scale and check the manipulation of creativity of activity. Two experimental questionnaire surveys were conducted to test the hypotheses. Findings of this dissertation have suggested that creativity interventions can be a double-edged sword in romantic relationships. On one hand, participants who rated a given activity to be more creative also thought more highly of their partner’s ability to help them self-expand cognitively, which in turn was associated with reduced relational boredom. On the other hand, those participants also rated their relationship to be more boring, perhaps due to a contrast effect. Additionally, creativity worked in reducing relational boredom only for participants who had been with their partner for a long (as opposed to short or moderate) period of time. Furthermore, it was perceived creativity of a given activity, not the activities themselves, that produced positive relational outcomes, suggesting that it might not be productive to search for one-size-fits-all interventions. Lastly, people’s innate tendency to feel bored and the degree to which they spontaneously connect themselves to their partner also affected various relational outcomes. Although there were limitations to the studies, the present dissertation has theoretical contributions to the self-expansion model and practical implications for those who aim at relationship betterment.