Relationships with a #NPD, #BPD and #HPD are like being the designated driver 24/7/365. All the relationship responsibility, all the time! They exaggeratedly profess their love for you, and then projectile vomit on you. Eventually, they grab the wheel and drive you into a wall.
To put it bluntly, being the "KeyMaster" in a relationship with a #narcissist, #borderline or #histrionic sucks. The burden of being the grown-up is on you. And, if you're a codependent (due to being a #ParentifiedChild), you're likely only too willing to take on this thankless job.
What are you getting out of this? What are you afraid you'll miss out on if you resign this voluntary position?