So how much of a cuckfest will this be.
Up to you as a player, that's the main thing I want to portray here. Play the male MC, play the female MC, play both. Keep them pure, corrupt one, corrupt both, its up to you. You want the femc to corrupt as the malemc stays pure and tries to save her go for it. You want to watch both fall and possibly capitalise becoming a monstrous demonic couple, totally there as much as staying true to one another and fighting for what's right.
The none corruption path is in no way an afterthought, I know a lot of other games have the "pure" path basically be just not seeing any scenes but my aim is for a "none cuck" path to itself have multiple possible endings of its own as well as engaging scenes between the two main characters.
Obviously you will miss out on corruption scenes but that's always going to be the case, in doing the corrupt stuff you'll miss out on pure variants and endings too, so in the end its down to what you want to see and how you want to play the game.