• Being promiscuous is a direct result of mental disease and low self-esteem.
Sexual Behavior in Borderline Personality:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3071095/

>Conclusion: The majority of the literature in this area suggests that in comparison with individuals without BPD, those with BPD evidence greater sexual impulsivity as indicated by higher levels of sexual preoccupation, earlier sexual exposure, more casual sexual relationships, a greater number of different sexual partners, promiscuity, and homosexual experiences.

• Being promiscuous increases risk of drug abuse:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3752789/

>interpersonal anxieties stemming from multiple (possibly failed) sexual partnerships may lead to substance abuse problems, especially for women.

• The impact of severe mental disorders (and psychotropic medications) on sexual health and its implications for clinical management
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5775119/

>In many patients, a lack of intimate relationships and chronic deterioration in mental and physical health can be accompanied by either a poor sexual life or a more frequent risky sexual behaviour than in the general population.

• How Many Sexual Partners Is “Too Many” Sexual Partners?
https://www.psychologytoday.com/us/blog/first-blush/201809/how-many-sexual-partners-is-too-many-sexual-partners

>Women tend to under-report their numbers
>Researchers have found a consistent negative bias against individuals with “higher” numbers of partners—we tend to view these people as poor choices for long-term partners or friends
>A recent study examined people’s willingness to consider someone as a potential mate (Stewart-Williams, Butler, & Thomas, 2017). A prospective mate’s number of past sexual partners had a large effect on individuals' rated willingness to get involved with them.
>Take away: There is a clear preference for partners with low to moderate sexual experience.