To why you create more than one path, well to love the feeling of losing something, you have to have a chance to actually get that something, if you can't get it (Andrea) before others (Jamal) you can't feel that "lost something feeling".
Besides what you don't want to understand is, that making something avoidable but later on in the game, would limite your player base. Not a single person would want to play the game if they don't like NTR/Voyeur/Sharing, because you made the NTR with Andrea unavoidable. So the only people that would be playing your game later on, would be the NTR lovers so they would choose the NTR path, making your other paths useless. For different paths to work, all the scenes should be avoidable until you choose the path, if you make the NTR unavoidable but says that later on it would be avoidable, it doesn't work, no one that don't like NTR would want "sloppy seconds" so unless you are making those paths just for you, I doubt many would actually play them, since your audience by that point would be NTR lovers, they would choose the NTR path, it isn't that hard to understand.