Well here's the definition via http://www.dictionary.com
pro·mis·cu·ous ( P ) Pronunciation Key (pr-msky-s)
1. Having casual sexual relations frequently with different partners; indiscriminate in the choice of sexual partners.
2. Lacking standards of selection; indiscriminate. Casual; random.
I have highlighted where I believe the source of subjectivity or discontent or interpretation or MISinterpretation lies... Who can argue successfully that men who frequently have "pre -marital" sexual partners could describe those 'activities' as anything less than casual. As opposed to always being about love, commitment and fidelity?
And should promiscuity be 'judged'? Which is supposedly worse? The casualness of those encounters vs the quantity? Is there a scientific formula? Is frequency of partners any 'worse' morally than just ONE 'casual' encounter? And just exactly what are those indiscriminant "standards of selection"? On and on it goes.... most sexual issues work in the man's favour.
I'm CERTAINLY NOT anti-men but you've got to admit there are more moral escape routes if you are male. Not fair.