Lol, might be wrong on this, but I don't think there ever was a 'proper swinging game' without the story putting heavy emphasis on the wife's cheating/cucking of her (usually) shit-for-brains husband and only giving him a few rushed, boring sex scenes, that are never as intense and passionate as hers, so I wouldn't expect to see too much actual swinging here either, and I do hope the dev proves me wrong eventually.
Nope. Was saying nothing as to rarity of swinging or proliferation of NTR.
I can't enjoy anything vanilla so I'm actually usually more into NTR than anything with happy sharing. I'd equally enjoy a pimping route. As long as someone is humiliated, forced, conflicted, etc. Doesn't matter if it's the guy or the girl, doesn't matter if they're the m/fMC or m/fLI.
The only thing that's opened my mind to happy NTS and the like and now making me interested in exploring western style swinging is actually the wave of sexy AI-NTS stuff like MNG, MR, SoA, UM... that are written well enough to make NTS relationships interesting.
Actually SoA in particular has very swingy vibes in the gym-scene if you're interested.