Romantic relationships matter more to men than to women: Based on Darwinian gender differences of fitness-enhancing effects in having sexual partners.

This commentary argues that the explanations for some important gender differences in romantic relationships offered in the target article are proximate instead of ultimate à la Mayr (). Combined with the ultimate ones based on Darwinian evolution, it offers a deeper understanding of the relevant factors. Other relevant factors include the higher availability of female prostitutes, cultural differences between the East and the West, and that women have menopause around the age of mid-40s.