A couple of points: First, the 72 virgins is a mistranslation, 72 raisins would be more accurate according to some Islamic scholars. What a disappointment that must be for the martyrs.
Second, you have done well to sidestep virgin media, virgin olive oil, however, is a good product.
And finally, the obsession among men with marrying virgins which was widespread on the Eurasian landmass and African continent, according to what I have read about tribal cultures and early civilizations, appears to derive from a belief that when a woman has sex with a man to climax, her womb was forever ‘tainted with his seed’ thus any children she had with him were not entirely his. It’s impossible to trace the origin of this but it still persists today among some tribal groups and was common in Europe until quite recently.
It also explains why terrorist groups like ISIS are so fond of raping females in occupied areas.