A research-informed mobile application (app) was created to encourage and activate couples to demonstrate healthy relationship behaviors in an effort to promote relationship quality, stability, and resilience. The app, Love Every Day, is grounded in the literature on couple quality, habit formation, and family resilience, and it uses tenets of effective behavioral intervention technologies. Forty-three couples (N = 86 participants) engaged with the app across a 21-day period and completed online evaluations, which consisted of a pretest, posttest, and three weekly questionnaires. Findings suggest that the couples' app promoted high levels of engagement, such that most participants viewed the app multiple times a day and also submitted answers to daily prompts 19.8 of the 21 days (94% of the intervention). Pretest and posttest assessments suggest that participants enhanced their relationship skills and behaviors, including knowledge of their partner's general well-being, care for one's partner, partner communication, and self-efficacy to manage conflict. Participants also reported higher levels of relationship quality after engaging with the app for 21 days, including less relationship distress, greater partner cohesion, better relationship satisfaction, and more relationship confidence. Implications for self-directed modes of relationship education and promoting family resilience are discussed.