She wants you as a girlfriend. To be there to assuage her guilt for leaving you for another man.
That's pretty much it. When we were still communicating, W had said something like "I really don't know how I'm going to get through this without you." I don't think she was (intentionally) being cruel with that one, but there's just no way either not break down or get mad at something like that. After my first marriage ended, ex-W was pretty much the same way ("I need you as a friend"). Believe it or not, I was stupid enough to try. I still have nightmares about what happened.
