The way it is written, you are mostly doing the cucking. But like as a narrator. So you will choose for Red and Daphne to have sex, but you aren't really playing as either, since when Daphne is with Fred you also make choices there, and when Daphne is with Shaggy you also choose, and when Red is with Velma you also choose.
So all that is to say, you are basically playing as a 3rd party watching Fred get cucked, but you get to choose how.
But you for sure are not following Fred, so you won't get cucked.