Seems like this really needs the cheating tag since both characters are going to be overtly cheating on their fiancé as the entire premise of the game.
I may as well ask directly the most obvious question, as I see no tag for it either. Is your fiancé going to get NTR'd and/or raped?
It gives strong vibes of that given everything (like literally the base premise of "you got engaged to your fiancé, but now..." and it'd save a lot of drama to clarify what's going to happen for the start with people.
You likely don't want to have people bitching/begging for/against certain content being added. Best to be clear for everyone so they don't get emotionally invested into the game and then feel they're being messed with if something is added/excluded later on.
I'm being sincere and not sarcastic in suggesting this, as the game looks like it could be very solid.
Also know what you're walking into/potentially enabling when some guy starts begging for a black man being added into the game (cuck fetishism). But if you're at the point of making a porn game, you probably know that.