I agree with Darren and confusedli, talking to her online is only dragging things out and making you feel bad. Tell her this, you shouldnt have to be subjecting your slef to these situatuations.
As far as harming yourself(Ive been there many years ago, know the pain). You may wnt to see a counsler on that, because that cant continue on and i think you are aware of that.
Like Darrren said there is probably or probably has been someone in your boat here, so keep on posting, its important to get your feelings out and not hold them all in, or you'll explode.
We are all here to listen and help the best we can....