I don't know about you, but i certainly get the feeling that Jacob manipulates her. After nursing her to a somewhat normal state during New Moon, its obvious he knows how she works. He has left his mark. Since he fixed her, he knows how best to break her.
Not only does he pick and choose when he talks to her, he doesn't even hardly give her the chance be angry with him. But then he goes and pulls the whole 'i'll go kill myself in that fight down there' card. He says Edward is playing a game, but the game is Jacob's, a game for some reason he's winning and losing at the same time.