Sometimes a game could easily implement alternative routes to every scene between the MC and other girls, on a consensual sharing context. It may sound like an easy "harem" approach but doesn't have to be, for example, the bakery scene could be recycled LATER if the MC stops it, eventually tells Suzy about it and she tells him to go ahead. The same rendering material could be used with a different text and, with the possibility of cheating still present, it allows for players to chose how they want to portray the MC and their relationship.
The problem with games that implement "virtue" in a lewd context is that, while you're playing to enjoy lewd or kinky situations, you're also avoiding some, often with double standards. In this case, the MC not only shares his girl, but even asks her if she's attracted to other guys (the bartender, for example), yet he seems to be afraid of sharing his own temptations with her. He even seems uncomfortable with them, which, in the context of their relationship, feels strange, as he could instead start wondering how Suzy would like seeing him getting lewd with other girls... As a character, Susy seems to be comfortable enough with it - the scene at the pitfire was pretty well written. It would be cool if sharing games also included cuckquean content with the FMC. Good game design would make most of it optional, by simply suppressing content we don't like, rather than making us choose between kinks if we're actually ok with most of them.
I understand some players prefer to focus on the FMC and would feel like cheating spoils their experience, and don't mind the game being focused about appreciating the FMC's lewdness, with the MC's role being secondary. Can't argue with that, it's about personal preference, only saying a game could be designed to appeal to both through choices, so that those who self-insert more and prefer not to feel like "they" are taking on a passive role can enjoy the full experience. If I wasn't clear enough, not saying there aren't people who can enjoy a passive MC, my whole point is that I don't, and would therefore prefer to have a path where the dynamic between MC and FMC were mostly balanced, while still focusing on the relationship - no harem needed.
