The thing is there's something downright disturbing in Stefan's motives. The whole thing really boils down to Elena is no longer 'pure' in his eyes. There's this whole, very old sexist trope lurking beneath this. If she's not this pure, good woman then he doesn't love her. So she has to be pure. It's... ugh!

Especially ugh is that it's a double standard because heads-up, Stefan ain't 'pure' himself. And if he wants to angst about that all the time, that's his business. But thinking that it boils down to Elena has to be all pure wonderfulness for him to love HER is icky. As icky as her having to be pure to save him. The whole thing undercuts the concept of you are who you are. You are what you do. And you love someone for who they are. He can't love her if she's in any way corrupt.

The whole underlying motivation is icky. That he's willing to do something so incredibly awful as to use Jeremy (whioch is corrupting both him and it's corrupting Jeremy-- against Jeremy's will) makes it WORSE. That it's corrputing him and corrupting Jeremy so that he can 'purify' Elena just makes me shudder.

If Stefan is meant to be at all rootable in this this, there's epic fail in the set-up.