Narcissists are insidious. They worm their way into relationships and they don't let go willingly. That's their real evil. They don't want to let go. They can't just allow someone to get out of the relationship; they have to make it as excruciating as possible.
The way to stay out of this kind of abuse is to leave as soon as they start the very early preliminary verbal denigration and so forth. Don't think they will change; they won't. Don't think you can change them; you can't. Don't think your love is enough; it isn't. Don't give them even a second chance. "*Leave.* Leave now and don't come back, while you can. Change your phone number and email and delete your Facebook profile. Don't respond to any contact attempts. Wipe them out of your life. That's how you can survive.