Shame I knew one just like that :-( And I always wondered why such a beautiful person was single. One learns from difficult situation :-( Common Symptoms of Sociopathic Personality Disorder - wow! Lying and having no remorse or guilt. What a sad, miserable life.
Codependency. As an INFJ, I have dealt with needy people being attracted to me and me being attracted to their sadness my whole life. I have finally broken free of it. I still have some needy friends but I keep them at more of a distance now.