Another big reason I have been there for her lately is to show that I can be. She felt the last few years I haven't been there for her as much as I should have.
In my opinion, you could still be there for her if she really needed you to be. But you will have to start detaching if you are going through with the divorce. You mentioned that if you were to separate she wanted to remain good friends but you couldn't see that happening. That is how I feel when it comes to me and my husband as well. If you separate you are going to need some space in order to heal/deal with the feelings of the loss of relationship, and most likely you will need space from her in order to do that.
Of course, you will have to remain friendly with her through all of this. With regard to handling details of the divorce, you will probably have to work through a lot of that together. As for personal issues, that is up to you if you feel like helping her/being there for her. You will probably want to detach somewhat, so you can start moving on with your life. I wouldn't be too eagar to help with everything she asks from you.
M: 8 yrs T:14 Twins:7 S:5 BD:'NLILWY': Feb/2013 Mar/Apr/May: MC June: "living in limbo" Sept 12: H moves out Oct 20: reconciling Jan-Feb 2014:MC Feb 2014: separating, and H moved out.