I figure I will address some of what has been mentioned in replies to my original post here.

Yes, I understand it is dangerous to play therapist, no I am not promoting my services in any way simply getting my experiences off my chest and hoping that perhaps they can help someone else. Likewise, it is worth noting that this individual could only go to therapy through her university and the person that was caring for her was very anti-therapy and forced her to not see a psychologist/refusing to pay for one. She had three therapists in a very brief time period provided by the university, one of them deemed themselves unqualified, one of them was extremely abusive, and her last one she saw briefly before being forced to quit. Her caretaker did attempt to hire a therapist for her, but since he does not believe in psychology he had M go to see one of his friends who is a psychiatrist and the psychiatrist did not believe her. I recognize that what I did was dangerous for her and would not advocate anyone attempting it, as I mentioned, however, I was around the age of 14 or 15 at the time which while not an excuse it speaks to my immaturity at the time. But M was dealing with something serious, she did not have any money of her own, everyone she spoke to had never met anyone with DID, and the therapists that did believe her wanted to have her take several drugs and try to remove her alternate personalities.

And while I imagine it is difficult to fully understand M's situation and what/why I did as I did: M and I were dating, she wanted my help, she wanted to open up with someone. She had never trusted anyone before, she had never had any non-verbally or physically abusive friends or family before. When I first met her she would ram her head into a wall until she went unconscious when she thought she did something "bad." My point being that M needed help from somewhere and while it was not desirable and I told her at the time it would have a lot of bad consequences for me to serve in that capacity to her. I was very clear with M that I was not a therapist, that I could make things worse, mess up, that she might end up in even deeper waters than before.
The post was meant to bring to light that it is very possible to have a cooperative, familial, smoothly functioning system with minimal conflict as well as to characterize my personal experiences with this person which are hard to share with others.
Also, I am no longer helping M in this capacity, primarily because I have evolved as a person since all of the work that I did was done.

Of course it would be extremely wrong of me to serve in an advisory role to something as complicated as DID, Depression, and PTSD. But personally, and you may feel differently, but when someone you love comes to you for help, for a problem they don't understand, when they can't afford to pay someone to make things better, when they are forbidden from seeing a real professional, I feel like that person deserves someone that is willing to at least be a shoulder to cry on and give some human advice, someone they can rely on and go to for help. And recognize, I was her boyfriend, in some fashion I was going to have to support her, I could not ignore it when she tries to cut herself, when she goes out at night alone to see if anyone will murder her.

So I will repeat, I do not recommend anyone doing as I have done, I do not think anyone other than a professional should try and treat any form of mental illness, I do not think an amateur should seek to diagnose another person. But she was my girlfriend, I hated seeing her suffer, she was aware of the consequences of what she asked me to do for her and so I did something because how couldn't I have done something in that situation.

Hopefully that clears things up, this is a topic extremely personal to me and so I recognize I probably sound very defensive, my apologies for that.