MBM, mathematically, men don't have to be promiscuous for a woman to be promiscuous. Promiscuity implies a one-to-many relationship. Thus, one women being with many men does not imply one man getting with many women. Hence, male promiscuity is not a prerequisite for female promiscuity and visa versa.
Women generally don't have a problem with male promiscuity as long as it is past tense. Many appreciate the skill sets from such exploits and in a sense, reward the behavior. On other hand, a man does not want a promiscuous women past or present tense, for as wife material, but only as their "bottom itchB". Therefore, promiscuous behaviors by women have much different consequences and risk than doe's male promiscuity. That having been said, all fornication and adultery are equally sinful.