Narcissists cannot be alone. Narcissists need people more than anyone. They have very specific reasons for being in relationships, but they are not built on the universal need we all have, which is to love.
Narcissists do not enter or stay in relationships for love. Their motives are quite different. They become involved in relationships in order to ensure their needs are met and someone is always present to provide them with the attention and adoration they require in order to feel alive.
It is important to understand when ending a relationship with a Narcissist, he will inevitably come back to you looking for validation. Whether you end the relationship or he does, you will most likely hear from your Narcissist again. It may take a day, a month or years, but be prepared for his return.
The only time a Narcissist finally leaves you alone is when he knows you have seen right through him and have exposed him for who he really is. If this has not happened yet and he believes he still has some kind of hold on you, he will return to you.