how/when to break it to him

all i've been thinking about is leaving. i'm about to just burst with the good news to him. haha. but now, am i being selfish? no, that's a stupid question at this point. but how do i handle the breakup? what do i tell my girl about it? what do i say to her? and what about moving out... divying up our stuff... moving on? i'm so sick n tired of still being here with him. i don't even wear my ring anymore, that's very symbolic to me. i put it on the other day, it totally felt foreign to me. when do i tell him?