Sure, and the analogy holds. In a sharing/swinging relationship you let your partner know where your boundaries are ("Don't do these things or these people"), she tells you where her boundaries are, and you respect each others' boundaries because you love each other. Crossing a boundary is cheating and breaks the trust and you wouldn't do that to your lover.
Agree fully. Was pointing out the OP was wondering why the MC could not set boundaries with Anna's relationship with her roommate in Italy. But you obviously get that and it is more about the narrative choice to not allow it. Which get me to my thoughts on the NTS path.
More than the other 3 paths this is the one that I did not vibe with as well as I thought I would. It was my first playthrough choice because I am not fan of typical NTR storylines. Cheating stories can be interesting but too often the MC responses in them leave it lacking. For the NTS path itself:
1) I felt really constrained on this path. The MC always is there to give Anna permission just in time, but the same does not happen in reverse. First one choice is removed via the above ban. Then two other encounters are coined as "cheating" due to the narrative around the MC. Which is fine but it means (especially in 1 case) that you have to completely abandon a potential romance and go friendzone. Would much prefer an option to say "Would need to talk to my GF first". But as becomes clear that is not there because of the MC narrative which makes this path an cheat or heavily restrict option. This could of course resolve itself in the future as perhaps the friendzone stuff reopens. But for now it is a path that is either heavily skewed or just feels bad.
2) The MC was almost a carbon copy of the Cuckold path in his responses and how he viewed sharing. Just seems to be the big recent trend that the NTS MC really wants to see his girl with other men and gets a lot of sexual gratification from it. Would have enjoyed a bit more choice options here. I loved that they communicated, cannot stress how cool that was. But to make it feel a bit different maybe the MC gives her a "Happy hunting" or Expresses concern before giving the go ahead. Options around the idea that he enjoys that she enjoys it. He knows it happens, but does not need the porn vid. "Have fun babe, but I am not quite in Turbo cuck mode". Its not a sexual thrill as he is not there himself. This is the most subjective and amounts to potential more work for the Dev that might not feel worth it.
3) The path seems to suffer the most from the premise of the GF being away. For me sharing SLs are better with all parties initially present to share the first experiences. With the plot premise it has to be experienced via remote, which perhaps contribute to the need for the MC to respond a certain way or it removes content. But I have to give way to the fact that NTS is not equivalent to Sharing/Swinging. There can be differences as defined by the author/dev.
I like the game overall, I think the artwork was great and I really enjoyed a number of the characters. They felt different from one another and over the 6 chapters we got to know a few of them very well with some interesting looks into others. The characters are well written in that regards and I give a real thumbs up here. The Italy side is obviously less built up but comments note that such will build up further down the road.