I think an instinctual reaction of "intriguing to hot" compared to "disgust to revulsion" has always been the case.
Plural women has always been the desire for the male of a species, in order to better spread his seed. Two women together presents the possibility of joining, which even in caveman days was a benefit.
This may be the reason today, but I am pretty sure it was not the reason in, say, the Middle Ages.
I think an instinctual reaction of "intriguing to hot" compared to "disgust to revulsion" has always been the case.
Plural women has always been the desire for the male of a species, in order to better spread his seed. Two women together presents the possibility of joining, which even in caveman days was a benefit.