In the context of romantic relationships, partners regularly observe each other's unsustainable behavior. But how do these unsustainable behaviors influence each member of the couple? This research shows that how consumers respond to their partners' unsustainable behaviors depends on the amount of relationship power they possess: high-relationship-power individuals compensate for their partners' unsustainable behavior by acting in a more sustainable manner relative to their baseline tendencies, but low-relationship-power individuals do not increase their own sustainable behavior. This effect occurs because high-relationship-power partners feel more responsible for the reconstruction of the couple identity after it has been damaged by their partner's unsustainable choice; as a result, they have a stronger desire to signal a positive couple identity (i.e., a positive couple sustainable identity). Consistent with this theory, this effect is attenuated for high-relationship-power individuals who have weak green identities. Seven studies provide evidence for these findings by measuring and manipulating relationship power and assessing hypothetical and actual sustainable behaviors. This research contributes to the sustainable behavior literature and highlights effective ways to promote sustainable behavior in households.