First time posting I need help...

I met my ex bf 5 yrs ago. We were together for 2 yrs and then he broke up with me telling me he "didn't know how to be my boyfriend" but that he wanted to remain friends. I told him I wasn't comfortable remaining friends because I wasn't over him and I needed a clean break. He said to me that he could not just be with someone for two years and never speak to them again, and that he was friends with all of his exes. He refused to go away, continued calling and texting me until I finally gave in. For the last 3 years pretty much nothing has changed as far as the difference between us being together and being "friends", with the exception of him no longer calling me babe anymore. He still continued coming over whenever he felt like it, mowing my lawn, changing the tires and oil in my car, doing all home repairs and pretty much making me completely dependant upon him. Whenever I asked someone else for a favor and he found out about it he would get upset and ask why didn't I call him. He would make me feel absolutely guilty about trying to do anything for myself. He recently put new wheels on my car, installed a new stereo systen and tinted my windows. I felt so guilty about always being the recipient and never the giver that I wanted to do something for him to show my appreciation for all that he does for me. I decided to go check out his fb page to get an idea of what he liked and needed, since he rarely ever talked about himself, which made me doubt his narcissism and consider perhaps my own. He was very good at making me feel like I was selfish and ungrateful for all he does and that I am emotionally abusive to him.

Anyway I went on his fb only to discover that for the last 3 yrs he has been in a relationship with someone else. This absolutely devastated me to the point of being physically ill. I have been in a deep depression for the last two weeks and sought out a therapist that pretty much told me that my ex is a classic narcissist. I always though narcissists were very rrude and mean spirited people and I didn't think he was. Now I see how absolutely controlling he was of every aspect of my life. This was a man that continued to sleep with me, lived with me for a year after we broke up, showed up to all of my two children's birthday parties, basketball games, took care of me when I was sick and so on and so on. He even stayed with me at the hospice when my father passed away in November and went to his funeral when I was too upset to go. He told me that he and my father had a long talk before he died and he promised him that he would take care of me forever. So for me to discover that he has pretty much been living a double life for the last 3 years has made me almost suicidal. I am even more pissed off at the fact that any time I began a new relationship or started dating he would always mysteriously show up at my home while my guest was there, sabatoging every potential future relationship for me, meanwhile carrying on his own for the last three years. He told me that his relationship was not a good one, he wasn't happy, blah blah blah. When I went and looked at her fb page she seemed to go through cycles of being over the moon happy, then frustrated and sad. She seems like a very empathic, caring easy going person and I feel as sorry for her as I do for myself, as I'm sure he's been as abusive emotionally to her as he has been to me. I don't know whether to tell her about myself , and that he is a narcissist that she should read up on about it or to just not say anything at all and let them both be. When I found out about her I confronted him and told him our "friendship" was over and to give me back all of my keys he had to my house and car. He completely freaked out at the idea of me leaving him and told me how much he loved me and couldn't live without me and that I was his best friend and that I know he is mine as well. He said if I left him he would never trust anyone ever again and that everyone always leaves him. I told him fine and that I would stay just to pacify him, and it's been a week now since I heard from him. I feel utterly lost and powerless and not the woman I used to be at all and I don't know what to do or how to move on. Please help me...