This is an old story. I have seen it all before. A basically well adjusted man has fallen in love with a woman who is traumitized by her past. Probably through a life of addiction and co-dependent, abusive relationships. She is emotionally crippled by her memories and unable to move on. The man has little experience with sort of woman and does not understand why she prefers chaos to the happiness he offers. Finally he decides he will not give up on her and vows to see her through this darkness. She leaves anyway, without warning, two weeks later.
I have seen this story played out before. Sadly the resulting confusion and hurt starts the man off on the same path the woman was already walking.