This will also help:

What is FOG?

FOG - Fear, Obligation & Guilt - The acronym FOG, for Fear, Obligation and Guilt, was first coined by Susan Forward & Donna Frazier in Emotional Blackmail and describes feelings that a person often has when in a relationship with someone who suffers from a personality disorder.

FOG - Fear, Obligation & Guilt — Out of the FOG | Personality Disorders, Narcissism, NPD, BPD