I'm sincerely curious. Why are so many people into NTR or sharing? I just don't understand the appeal. I'm not kink shaming!! But, to me it would be immensely emasculating to watch another guy laying his pipe into my women.
I'm not into watching a good man written as a wimp who gets nothing and whose girl gets hammered by assholes until she abandons the MC. That kind of story is just not entertaining for me, no matter how good the pictures are. However, this is a video game/VN. The wife is not my RL spouse. She is a character in a game meant to titilate. NTR or NTS, Harem, Sharing,... it's all about watching fantasy, hopefully with an engaging story.
The MC in this one is very open and casual about hooking up with any woman he is standing next to, all of whom are quite into it. Why not watch others involved in the orgy? Why must the story require that all those willing lustful female characters only allowed to play with eachother while none of your friends and comrades get any? So what if the MC's wife gets in on that? It's not like the MC is lacking in options for fun or stress relief, and its not like the MC's wife is the players wife IRL.
Kind of hypocritical for the MC to be caught banging his students in the bathroom, then get pissed and tell your wife to pound sand when she, a driven archeologist, is abandoned by the MC to do a ritual to go into the past that unfortunately requires a dudes involvement, and the MC refused to help her. She has to go, that is the whole point of the plot. Besides, the MC's wife model is nice to look at, and watching her in sexy situations is fun.
Its all just on screen fantasy played out for your visual enjoyment. Just enjoy the show.