Previous studies on romantic love have reported increased neural activity in the brain's reward circuitry such as the striatum. To date, the extent to which this activity is modulated by couple conflict in general and mediated couple conflict in particular, is unknown. The present study seeks to fill this gap by randomly assigning 36 romantic heterosexual couples to a mediated or non-mediated conflict discussion. Before and after the conflict discussion, self-reports and functional neuroimaging data in response to a picture of the romantic partner versus an unknown person were acquired. Self-reports indicate that mediation increases conflict resolution, satisfaction about the contents and process of the discussion and decreases levels of remaining disagreement. Pre-conflict neuroimaging results replicate previous studies on romantic love, showing activations in the striatum, insula, anterior and posterior cingulate gyrus, orbitofrontal cortex, hippocampus, temporal and occipital poles and amygdala when viewing the romantic partner versus an unknown person. The general effect of conflict on neural activations in response to the romantic partner across both conditions consisted of deactivations in the striatum, insula, thalamus, precuneus and ventral tegmental area. Small volume correction analyses revealed that participants in the mediated condition trended towards having greater activation in the nucleus accumbens than participants in the non-mediated condition when looking at the romantic partner versus the unknown after the conflict discussion. Parametric modulation analyses also revealed greater activity in the nucleus accumbens when viewing the romantic partner versus the unknown for participants who felt more satisfied after the conflict resolution. Our results illustrate that mediation improves conflict resolution and is associated with increased activity in the nucleus accumbens, a key region in the brain's reward circuitry.