Babbling

I know it's normal for people to repeat stories to the same person without realizing it, but it can get really annoying after awhile. My boyfriend can't remember shit so sometimes he tells me the same thing like five times while forgetting that he already told me four too many times. At first I felt rude telling him that he had already told me something, but now I want to hit him every time he tells me something for a second time. I don't know if I need to start writing down what he tells me so I can just give him a list of stories not to tell me or if I need to keep telling him I've already heard the story. Whatever I end up doing I need to do quickly or I'm gonna end up going postal on him for hearing a repeated story. To most people this probably sounds like something minor to be getting pissy about, but just to show you how crazy it can make you, I'll let you borrow him for a week or two and see who comes out sane. I bet it'll be him.