The covert narcissistic is in some sense more dangerous because you do not seem them coming. They act as if they care, they act as if they are committed, they act as if they love you, but they have been so injured that they have been left apathetic. As they age they may act out or may also act out by replacing their significant other and toss them aside in exchange for a better supply. The "better" might be more beautiful, richer, more gullible, and more relatable. They don't tend to stick around people that expose their fake self.