Mate-choice copying is a phenomenon whereby females assess the mate quality of males based on the mating decisions of other females. Previous studies demonstrated that the presence of a partner enhanced men’s attractiveness. Mate assessment is, however, error-prone, and the accepted male may turn out to be of poor quality after the relationship has progressed. This study extended the previous research by focusing on more reliable social information about male quality as a long-term partner: duration and interval of past relationships. Japanese female students (N = 201) were presented with a male profile containing information about past relationships, and they rated the target males as long- and short-term partners. The results confirm that information about a man’s long past relationship enhances the women’s desirability ratings for that man as a long-term partner. It was also found that a man with a long relationship was preferred by sexually inexperienced women, even in the short-term mating context, if the interval between the man’s past relationships was long. The study findings show that female mate choice is influenced by information about males’ past relationships, in addition to the information about male’s past partners discussed in previous studies. The finding for short-term mating suggests that it is used as a foothold for long-term relationships by females who may have lower mate value. The findings of this study add a new aspect to the non-independent mechanism of human mate choice.