The Science-Backed Secret to Long-Term Passion
Psychology Today
by Justin J. Lehmiller Ph.D.February 23, 2026
AI-Generated Deep Dive Summary
The article explores how self-expansion—growing through new shared experiences—plays a crucial role in sustaining long-term passion and sexual desire in relationships. Initially, romantic relationships often start with intense passion, but over time, this fades as couples settle into routines. This isn’t about losing love but rather the decline of novelty, which can dampen arousal. However, introducing new activities and fostering self-expansion can help reignite passion. Self-expansion involves expanding one’s sense of identity and skills through shared experiences with a partner, such as trying new hobbies or exploring different perspectives.
The article explains that self-expansion goes beyond mere novelty by creating excitement and breaking predictability. When couples engage in challenging or unfamiliar activities together, they introduce uncertainty and surprise, which can change how they perceive each other. For instance, discovering a partner’s unexpected skill or trait during a dance class can reignite attraction. Additionally, self-expanding activities strengthen commitment by making the relationship feel enriching rather than limiting. This growth fosters curiosity and keeps partners motivated to invest in their connection.
Research shows that couples who engage in self-expanding activities report higher sexual desire and greater relationship satisfaction. Even non-sexual experiences, like taking a cooking class or going on an adventure walk, can boost arousal through the excitement and novelty they introduce. This “misattribution of arousal” effect means that the physiological stimulation from new experiences can transfer to increased sexual passion.
For readers interested in health, particularly mental health, understanding self-expansion’s role in relationships highlights how growth and connection contribute to overall well-being. By embracing new experiences together, couples can sustain desire, strengthen their bond, and enhance their quality of life. This approach not only keeps relationships vibrant but also supports emotional and sexual satisfaction over time.
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Originally published on Psychology Today on 2/23/2026