From experience, the options for dealing with these situations boil down to personal choice really. If the person you believe to be a narcissist is so close that you know you cannot keep a ‘safe distance’, then you need to find a way to look after yourself. If they are someone that you could imagine seeing less of, or relying on less, then finding strategies to do so is absolutely necessary.
For a very close relationship, @mrentropy‘s response is simple and to the point. It takes work, but can be done. For the less close, then the more distance the better, for your own wellbeing. It is simplistic to label all narcissistic people as ‘emotional vacuums’, they are not necessarily that – more likely they are terrified of being exposed as tiny, vulnerable and weak. As I write I just saw @lucillelucillelucille‘s response…Hoho, I have a sister by that name…!!! She’s only slightly narcy… Small doses is it though!
Never, ever beat yourself up over how you feel or respond to this person. They won’t care any the more for your pain. Empathy is simply not in their capability, any sense that they are ‘feeling sorry for you’, will be based in what emotional pay off they believe they can get for themselves. It is a truly unpleasant situation to be in.
Just a back reference to my earlier comment about weakness and vulnerability, I believe that true narcissism is considered to be rooted in childhood at two specific points. The 2 year old (terrible 2s) and at age 6. A 2 year old can take charge of a whole room with a horrible tantrum… a 6 year old loves playing ‘king of the castle’. If useful, healthy responses are not given to each, then either may remain emotionally entrenched at these unhelpful stages in development.
It may help in dealing with your narcissist to imagine them as a small child… And behave gently, but appropriately. As long as you can avoid patronising, they may well be grateful.
Good luck.