Fable II on Xbox 360 has no split-screen, shared-screen, or local co-op multiplayer. It is a strictly single-player experience. Lionhead designed the narrative and systems (dog companion, moral choices, property ownership) around one hero.
If you want shared-screen Fable, Fable III (Xbox 360/PC) supports 2-player local co-op with a second hero who can import their own character or use a henchman.