I get what you mean but that won't be an option. The player DOES sort of disengage from taking things further in ch5 ( with Maple ) Because at that part there is more of a clear relationship, and then the plan is to build things so the player can get intimate with others and hopefully not feel bad.
If I decided to make a 100% monogamy path I would need to restructure the game so much and cut so many scenes in the final product, and I imagine 99% of people just want as many scenes as possible.