She won't initiate sex

My wife never, or rarely, initiates sexual contact, or any physical intimacy. We never have sex spontaneously – it is always discussed and planned first, teeth cleaned, undressed, into bed and then I know I need to initiate all the ‘proceedings’. Every six months or so, we discuss our sex life and my wife promises that she will try to initiate sex more often. But after such discussions we may have 3 or 4 days before my wife remembers that she is ‘supposed to be initiating’...