Louisa, welcome to our little place. You have already recieved a lot of good advice so I am going to just voice my concern. I am worried by the fact that her conversations with you bring up a desire in you to hurt yourself, too. I am also concerned with how she is trying to control you by saying you are the only one she can go to. This isn't a good situation for you to be in. I have this feeling in my gut that makes me want to say to you that you should back away from the relationship for your own wellbeing. But I know it isn't that easy sense it is obvious how much you do care about her. I think it is important that you develop some bounderies. If her talking about SI creates that desire in you, it is important to tell her you can't talk about it anymore but you are still willing to talk about the underlying feelings. Tell her about this place. Let her know that we have all gone through this. We won't know who she is, or where she is so she is safe talking about it here. If she refuses to seek other support that is her choice. She is choosing to stay sick and she is choosing to try to keep you in the middle of it. That isn't your fault and there is nothing you can do if she decides to not get better. You, however, can choose to place your own wellbeing first. If you keep yourself as well as possible you will be more help to her.
Carrie

<font color=green>But the implicit and usually unconscious bargain we make with ourselves is that, yes, we want to be healed, we want to be made whole, we're willing to go some distance, but we're not willing to question the fundamental assumptions upon which our way of life has been built, both personally and societally.--Bill Plotkin, Soulcraft