My thoughts on this is that there are half a dozen reasons why people could be into NTR, but the most likely and common would be that these people are Bi-Sexual weather they know it or not. They're turned on by the women, but they get even more turned on by adding another male. In this scenario there is only one variable that changes, that of the other male being added so they are being excited that bit more by the male. Not that I've got a single problem with such, but they should try to remember that it's a (huge) turn off for others. And if they aren't going to leave path/s in the game where you wont see any of this then label the game correctly.
I mean honestly I'm not trying to sound all smartypants here(or internet lie about it because really who cares) but I've actually got a degree in psychology(one day I'll be a dick and review that Psychiatrist game from a medically correct standpoint) and yeah honestly what you said is kind of human psychology 101 type shit.
Obviously there isn't anything inherently wrong with it but yeah the reason is that cuckolding and
BIG BLACK COCK focuses so much on other guy's
giant penis is because yeah s huge chunk of it is meant for and consumed by either homosexual or bisexual indivuals or those who have a subconscious sexuality they aren't really sure of or willing to admit to publicly.
The people who make the type of porn and other stuff know this as well, which is why they focuse so much on said aspects of it in their porn, usually using an uncomfortable female to act as the standin for the second male due to the whole masculinity thing people don't want to give up on.
Similar to all the stats that show how people who seemingly hold bigoted beliefs are
really into black porn.
(why did I just write a whole human sexuality thing on a freakin' porn game forum)