I kind of agree. For me the whole thrill on the cheating route in Pineapple Express was about not really knowing what the wife was up to.
The scenes when MC walks into Cornell's room and sees used condom on the bed, or when he sees Cornell adjusting the camera, so it's not pointing on the bed anymore, and then hears weird sounds, or when he comes back to his hospital room, and sees wife's underwear lying beside the bed and her cuddled tight with Cornell (naked obviously) were really hot, because we didn't know what really happened and imagination was going wild. And that's what makes it for me the best game in the genre so far, although I still didn't play Sharing My Fiancee, so I don't know if it's similar in that area. But, as you said, we can turn the wife's perspective off, and if Dimajio made that an option, I'm sure we can have similar experience to Pineapple Express. The perfect solution I think would be playing the whole game from MC's perspective, and seeing what really was going on behind the closed doors only after finishing it.
PS. As the genre fans, maybe you can recommend some games similar to PE, with kinds of scenes I mentioned in the spoiler