Why does a narcinist girlfriend leave you at the table and socialize through the restaurant all evening?

Narcissistic women aren't much different than men who are. They are selfish; self centered; ego maniacal and only do things for themselves that make them feel go. Since you already know she is selfish and self centered and consider her a narcissist then it's better to break up the relationship and move on because these types of people will stop on you every chance they get to get what they want and don't care how you feel. Eventually the narcissist will dump you and move on.