Valexand, hunny, as I read your post, I identified with much that you described, especially the long recovery. Since I've been in that place in which you find yourself, but I'm now recovered and thinking differently, I'm going to say some things straightforwardly to you:

This man with whom you had this 4 year relationship, was emotionally abusive. I can think of nothing more painful and abusive than having to witness a girlfriend living in your presence with him for three weeks. I call it Narcissistic and even sociopathic on his part. Also, the fact that he "hid" the relationship he had with you, limiting it to the bedroom is emotionally cruel. Have you ever considered why you tolerated this situation for such a long time? Have you tried to talk to a counselor or done self-study in books on these kinds of issues in relationships. I ask, because, at one time, I had a whole library of such recovery books, and I worked so very hard at understanding my own mindset.

This man was your "first." I had a similar first, who was very emotionally abusive. Part of this mindset, I think, in retrospect, is that some of us females put such importance on the first, thinking of it as a sacred bond. Obviously it isn't with such men. Then we are left to recover. And it is a shame that you are still hurting and wondering after 4 years. I've been there and done the same. I recognize that some of this relates to low self-esteem, thinking I didn't deserve any better, while I watched other women my age go on to happy marriages and having families, building the dream.

I say to you, do not let this man rob you of any more of your precious time and your youthful womanhood. He truly does not deserve another moment of thought from you. I've had more than one such relationship, so I know from where I speak to you. You WILL reach a point where the very thought of this man is no longer important to you. You will think of him with indifference, which is better than love or hate. It means you are recovered! Think on this.
Love
Patty