That sharing scene was just one route of 1 single scene. Everything else related to the porn has been driving towards NTR/cheating. I'm sure there will be more chances to do some sharing with Dave when the story dictates them to go somewhere together, but saying that was the main focus is simply not true.
The main thing that stands out in this game is the masterful build up of sexual tension and a the choice system that stays within character. She doesn't just random decide to fuck some guys just because she felt like it or because they want to rape her. The choices are a slow build up of conditions that will lead to a pivotal moment where the player doesn't have to directly tell her to cheat. She succumbs to lust based on past choices (often fairly innocuous ones that can make sense for her character in those moments) that the player has been building up. That is a subtle difference, but one that has a huge impact on how we perceive her arc towards unfaithfulness. It tells a perfectly paced slow corruption story rather than the usual "slut-em-up" you are talking about.
I could see and concede your first point, a lot of the earlier dialogue prompts hint more towards cheating/flirting with disaster, I guess I was just hoping for my own personal preferences it would track in the direction of swinging side and less the cheating - but yeah the hints are definitely there with Ollie & co.
On your second, I strongly disagree. Taken in full, in the game's current implementation, there's no sense of innocuous choices or things making sense in the moment. Ironically, that's the same wording I'd use for why I liked the Ch4 leon scene so much, it made sense in the moment, girlfriend and bf's friend flirting all night and drinking, then he joins in during mixed signals between the couple.
In contrast, Alice entertaining caveman-style advances from Carlos or Frank is the exact opposite of what one would expect for someone who looks like Alice, her age, her personality, Outside of the context of porn games, this setup would be seen so obviously for what it is - a plot device to set up the token bbc sex scene. This intent is made transparent later on when Alice is deciding who to text and says something like "I want to hang out with someone, there's no way I can talk to Leon, hmm let's see what Carlos is doing" - Yeah, my bf's friend who I messed around with prior is 100% bad news, but the fat old cop who slaps my ass, that sounds far more appealing...
