Accept it for what it is. Not everyone reacts the same to every situation. As long as she still treats you with respect you should appreciate the forgiveness they have in their heart.
All you can do is voice your concerns and then move on. As a friend you don't want to see th get hurt but you can't stop it. So you have to decide if this is something you can support or if you have to create some distance for your own sanity. I have had to do this and I just quietly pull back and check in on the person periodically so they know I am still there for them.
Let it go or cut them both loose. It really is that simple.
I agree.. Good lesson to learn here is concentrate on who you want to or don't want to forgive and let other people make that option for themselves as well. It will save you many friendships in the future. Though I have noticed that woman are less able to do this then men, woman really do seem to have a need to have the whole group turn on a person.
That is a bit complex...but from the outside I would say drop them both and move on... I have found that no good comes out of relationships where someone is abused and you try to step in.
Nothing - They're big people and it's not their argument it's yours. You cannot expect people to take sides that's unfair.
Again it's up to them! They have a head on their shoulders!
All you can do is keep your own counsel. If they ask you for advice make sure it's impartial.