One longitudinal study of married couples and one experiment tested the hypothesis that the experience of sexual desire for an alternative sexual partner might heighten feelings of desire for one’s long-term romantic partner, and conversely, sexual desire for one’s long-term partner might heighten desire for alternative partners. A daily-diary study of newlywed couples revealed that (a) on days people reported heightened interest in alternative partners, they also reported increased desire to have sex with their partner and (b) on days people (...) reported heightened desire to have sex with their partner, they also reported increased interest in alternative partners. An experimental study of partnered individuals revealed that people primed with sexual desire for an alternative partner reported increased sexual desire for their romantic partner (relative to a control condition). People primed with sexual desire for their romantic partner, however, did not report increased sexual desire for alternatives. Taken together, these findings support evolutionary perspectives on the function of sexual desire. Findings are consistent with the broader hypothesis that sexual desire is not partner-specific. (shrink)