The empath has to realize the bitter truth that not everyone deserves their love, care, and affection. Not everyone who seems distressed and unhappy is revealing their true self. There are some people who have sinister motives and have a very different outlook towards relationships and people than they do. Not everyone they fall in love with can be trusted so quickly.
In this situation, the empath must realize that they too are in a very bad situation something of which the narcissist in their life always spoke of. But, in their case, it would be different. They would make positive efforts and heal themselves. The narcissist will not.