Eighty-one participants were recruited to test the sensitivity of the mating sociometer to mate-value feedback in the context of ongoing intimate relationships. Experiences of social rejection/acceptance by attractive opposite-sex confederates were manipulated. The effects of this manipulation on self-esteem, relationship satisfaction and commitment, perceptions of dating alternatives, and friendship-dedication were assessed. Social rejection/acceptance by members of the opposite sex altered relationship satisfaction and commitment; this causal link was amplified by changes in state self-esteem; and these effects were specific to intimate relationships and did not generalize to friendship-dedication. This research supports a domain-specific conceptualization of sociometer theory, extending the theory in important directions.