The only sure-fire way I know of to deal with a romantic partner intent on involving me in drama is to sever the romantic relationship. For me, that works--after a few false starts, I'm with a girl who always cooperates in tracing our rare disagreements back to a root difference in either factual beliefs or values, and resolves it with wikipedia or compromises, respectively. But my approach strikes some people as unrealistically draconian.

Is there a more subtle set of skills than "only become involved with rational people?"