You said:
“For a lot of straight men it’s still all about them, their dicks, and the paternity of their offspring. Girl-girl doesn’t count because it’s not involving them, not involving their dicks, and doesn’t affect the paternity of their children and therefore isn’t really sex.”
First, what is “a lot of straight men”? Is that the majority? Or just a non-negligible minority of them?
Second, however many there are of such men, you claim that for these men, “it’s still all about them, their dicks, and the paternity of their offspring”. So, these guys don’t care about STD’s? If their wives were sterile, they wouldn’t mind the wives having sex with tons of other guys, since there would not be an issue with the “paternity of the offspring”?
I think you’re just wrong that there are that many men in monogamous relationships, who’s only concern wrt their wives’ extra-marital sex is the issue of offspring.
It seems to me that the reason so many men seem to be OK with their wives having some girl-girl sex is not because of the offspring issue, but because, due to societal changes in the past 10-20 years, girl-girl sex has lost its taboo, its “bite”, its stigma.
I assume (and I’d like to see studies/surveys on this) that most men would have not been OK with their wives having sex with another woman back in the 40s or maybe even 80s. Just like most women today are not OK with their husbands having sex with another man (even though there is no possibility of offspring from those relationships, which according to you is the only deciding factor for “a lot” of people)
There’s nothing special about what’s going on today, and it’s funny that people try to find rational reasons why people are OK with girl-girl sex, when in other societies the reverse was true: e.g. in ancient Greece, it was OK for guys to have guy-guy sex, and still end up in a marriage with a woman. Guy-guy sex was not a taboo, it had no stigma, so guys did it, and women were not bothered by it.
As to why guy-guy sex was OK in ancient Greece and girl-girl sex is OK in 21st century USA, I don’t know. That would be an interesting question for sociologists to answer.
But the reason girl-girl sex is OK today is not because there can’t be any offspring.