Only you can truly say it is time to divorce your narcissistic wife, it’s up to you to make that decision. If you feel you can no longer continue with your wife’s behaviour, you should leave, but if life is bearable with your wife and you can just take some time way from her or you can limit the time you spend together, it would be easier on you.
For you to divorce your narcissistic spouse you need to be sure you are emotionally and mentally ready for the irrational behaviour your wife might put up. She might become more resentful and spiteful than ever.
Does your wife have a diagnosis from a consultant psychiatrist of narcissistic personality? Otherwise this sounds like an abusive term you are using to demean her. What personality description does she use for you?
If it is equally unpleasant, then it certainly sounds as if there is not enough love between you to sustain the marriage any further. Perhaps consider why you married your wife, what her positive attributes were (besides looks) and what she has contributed to the marriage emotionally and practically.
Then consider what you have contributed to her as a person. There seems little point in prolonging a marital relationship that has no love or respect in it. The decision about divorce must be mutual, of course.
If it is impossible to hold a rational and civilised discussion about separation with your wife, then use professional services and move forward.