There’s no way a feminization game like that doesn’t exist. Unfortunately, I feel like they all are NTR with really aggressive humiliation. Would be hard to make it work in an NTS perspective unless it’s already known the MC is bi already.
Would be hard to write someone being uninterested in men to being bi in a week. But hey, NTR writers and begrudgingly NTS writers, make innocent girlfriends/wifes into sluts after one discussion.
About two years ago I saw a discussion on a forum about a romance novel where the theme was an obsession/fetish a wife developed. She started dreaming and getting aroused whenever she thought about her husband having sex with other men, haha, and the detail is that in her fantasies and daydreams, her husband was always the passive partner, haha.
In this case, the wife has a kind of reverse cuckolding obsession homo, haha. It seems that some situations in this book led the wife to develop this strange fetish, haha.
I don't remember the name of the book, but it seems to have been very successful among women.
Apparently, the wife's desire becomes so strong during the plot that she hires two men to drug her husband's drink so he can be violated, and she can film and watch everything while masturbating.
In this case, these men weren't criminals; she tricked them by saying her husband was bisexual and loved being passive with men, and that this whole setup was a gift from her to her husband.
She did this because she had previously tried to talk to her husband about her fetish, but since he became furious and threatened to separate, the wife resorted to this insane act.
A plot like that would be believable in a porn game, but I doubt a developer would do something similar.