I want to recommend another interesting and informative article by Shahida Arabi (who wrote What Abuse Survivors Don’t Know: 10 Life-Changing Truths, which I posted a while back):
Your Brain on Love, Sex, and the Narcissist: The Addiction to Bonding with Our Abusers
Many survivors of narcissistic abuse are confounded by the addiction they feel to the narcissist, long after the abusive relationship took a toll on their physical, mental, and emotional well-being. Make no mistake: recovery from an abusive relationship can be very similar to withdrawal from drug addiction due to the biochemical bonds we may develop with our toxic ex-partners.
Understanding why we are addicted permits us recognize that our addiction is not about the merits of the narcissist, but rather the nature and severity of the trauma we’ve experienced.
Read the article in full on her website, Self-Care Haven for Survivors of Abuse and Trauma.
I recommend taking a tour around the site, since she has some great articles and resources there!