So im guessing the original games protagonist is trying to go for the reverse harem ending which is why she's trying to separate our girl and her fiance. The original protagonist really dose come off as creepy and manipulative when you see her from the rival girls position. Also I think the original protagonist really does know what shes doing, i dont know a girl thats that dumb to matters of relationships. But thankfully our based boy dosen't seem to be falling for her tricks.