For me that's something I really like. Not only is there something very satisfying and sexy in seeing YOUR women pleasing and getting pleased by each other, it just really is the only thing that makes sense in a relationship with only one dick and so many "mouths to feed".The only criticism I have for this VN personally is there's too much girl on girl and it feels more like a poly relationship then a true harem.
I will say though, I also really enjoy it when the girls say that doing it with other girls is great but that they prefer bumping privates with me even more.