Bleed them, over a weeks time, slowly draw their blood from them. the feeling is dizzy and lasting, its somthing that would torment them, or do the old school thing, drops of water endlessly until he/she gose insane but it takes some time. or both. however if your really want to hurt someone and have them feel it for their whole life, go with emotional, not break their heart, but study them, then when the moment is right make everything dear to them disapear, make them feel like their worlds falling apart.
but thats just what I´d do (for fun some times)