Romantic relationship quality declines over time for most couples. In addition, most first marriages end in divorce, and divorce rates have doubled during the past few decades among people over 35. Identifying interventions that improve compassionate love, empathy, and prosocial behavior between romantic partners is thus a critical goal. Our overarching aim is to experimentally test whether a mindfulness intervention improves compassionate love, empathy, and prosocial behavior between distressed romantic partners relative to an active control comparison. Distressed romantic couples from the community will be randomly assigned to one of two arms: mindfulness vs. active control. Both interventions will be completed on a smart-phone for 14 days using identical intervention activities as our existing published research. After the 14-day period, couples will attend a lab visit and complete the Compassionate Love scale and an adapted version of the Toronto Empathy Questionnaire. Couples will also complete a conflict discussion, a paradigm commonly used to assess objective relationship processes. An adapted version of the Rapid Marital Interaction Coding System (RMICS), will be used to assess compassionate love, empathy, and prosocial behavior during the discussion. If our aim is achieved, we will have identified a scalable intervention for enriching people’s romantic relationships.