It seems a bit unfair to try to blame or call out those who didn't like the direction the wife was taking as the reason why the dev did this reset. As people have mentioned, even on the MC faithful path and only sleeping with those the game forces the MC to sleep with, the wife still cheats and seems to show no remorse while falling further down the rabbit hole. The reason some feel more upset about the wife's behavior then the MC is because, as many others have mentioned, we have no idea what the wife is thinking and what is leading her to do what she does. While for the most part the player's actions control what the wife does, she will still 'cheat' so it's not unreasonable for some players to feel a bit jilted at the direction things were going. The choices they made previously basically amounted to nothing and there's no way to avoid what the wife does. I think a lot of people mistake the complaints as them not liking that she's cheating/being a huge whore when the truth is closer to them being frustrated that their choices don't really matter.
I don't think the reset spells the end of the cheating route. It will still continue on similarly to how it was before said reset. Most likely the reset was done in order to try to clean up the paths/routes. As it was prior to the 'reset' there were basically only two paths. Cheating or cuckold. The reset is an attempt to be able to try to re-introduce the faithful/sharing/swinging paths in a way that they don't get lost in the shuffle and clear boundaries can be laid out between the various paths. While it's still a band-aid fix and there still remain numerous continuity errors, flaws in logic, and major issues that have been glossed over that could have provided some much needed tension and conflict, it would seem at least there's an effort to try delineate the various routes so there can be actual different endings.
I mean their discussion when they were 'honest' with each other wasn't even the full story and all the relevant details. Things that could have been big sources of conflict and drama weren't addressed and they kind of only offered the bare minimum information in order to try to salvage what they had. Who knows, maybe the wife only brought this up as a diversion so she could cheat/cuck him more now that he's kind of let his guard down and feels better about their relationship. Or the MC just pretended to be ok with everything but he's really super pissed and will now go fuck her mom/family.
Basically I wouldn't worry about the cheating route being removed. I'm certain the next update will have them pick up right where they were before the reset for those that want it. The only thing that will change is for those that don't want that they may have an option to pick the other routes and won't be forced in a direction they don't want.
I just wish the dev could have seen this coming and planned accordingly instead of basically having to retcon the story when it feels 3/4 of the way finished.
