I've seen progressives shame males for not wanting promiscuous partners with "You're afraid you won't satisfy her."

In this is an implicit concession that promiscuous females take more effort to satisfy than chaste females. (I use the term females here as I feel it is more inclusive than women)

Given that you expend more effort for the promiscuous female, what does the promiscuous female give you that her chaste sister doesn't in return for the extra effort?