Inspired by research showing that wanting (one's motivation to engage in an activity) often diverges from liking (one's enjoyment of the activity), this article details the development and validation of a new measure to examine the distinction between sexual wanting and liking within a relationship: the partner-specific sexual liking and wanting (PSSLW) scale. In Study 1, participants (N = 1145; 63% female) completed items intended to measure PSSLW. Factor analysis supported a 15-item two-factor solution that explained 64.7% of the total variance. The partner-specific sexual liking (PSSL) subscale (Cronbach's α = .93) and the partner-specific sexual wanting (PSSW) subscale (Cronbach's α = .87) showed good internal validity. Test-retest reliability on a subsample (n = 30) was high (Pearson's r = .75). In Study 2, participants (N = 67; 71.6% female) completed the PSSLW scale and additional measures of satisfaction and desire. Both scales displayed satisfactory discriminant and convergent validity. In Study 3, participants (N = 2589; 45.3% female) completed the PSSLW scale and answered questions about sexual behavior within their relationships. The two subscales were distinctly correlated with measures of self-reported behavior. Moreover, confirmatory factor analysis (CFA) yielded a good-fit two-factor model, where the Comparative Fit Index (CFI) = .97, Tucker Lewis Index (TLI) = .96, and root mean square error of approximation (RMSEA) = .06. Data from these three studies suggested that PSSLW were distinct, measurable, and valid constructs that have the potential to enrich future studies of sexual experience and behavior within sexual partnerships.