I think everyone that lives long enough has to come to terms with the fact that their life won't continue on forever. Unfortunately, imo, those of us with MS need to come to terms with this long before most "regular folk".
Sally as we know getting old ain't for sissies and geez getting old with MS is really the icing on the crap cake many days however like you wrote, the great news is that your wonderful family definitely gives you something to stick around for.