Hello. I've read all of your updates. I'm so sorry your wife has moved out.
GD can make one feel very very unhealthy and frustrated but in all honestly, I personally feel that it is probably the “last drop” as they say. In other words, the disease, like anything else that causes high emotions, such as a new baby, cancer, etc., will only intensify what is already going on in the relationship. Having said that, it could be that your wife already felt the way that she does now but that the disease experience along with other events has allowed her to actually act on it. The getting sick and completely changing ones personality to the point to seeing other people and wanting a divorce reminds me of how a person would act if bipolar. I have read about GD affecting ones memory but I haven't read anything about one acquiring bipolar like behavior, though I may be wrong since I'm so new with GD.
You mentioned that you have older daughters and I'm assuming you have been married for a while. I've read and I have also been told by friends who are psychologists, that divorces tend to happen at certain times and one of those times is when the children are grown and moving out of the house. In those situations divorce some times happens because it is at that time that one of the parents feels that it is safe to move in the direction they have maybe wanted to move towards for some time but had not since he/she was afraid of how it would affect their young children. I'm not saying that is the situation in your case but it is something to think about. It can also be that the courage was just not there and being sick has made her think about what she wants her future to be like.
Since she has moved out and has asked for some space, I personally think that as long as she is seeing her Dr and taking her Rx, that she should be given the space and time she has asked for. After all, she is a grown adult. I think I remember reading that she is seeing someone else though? In that case, I think I personally would just want to move on and let her take care of herself. That is just me though since I'm of the opinion that there are some lines that just should not be crossed in a marriage.
I wish you the very best healing from all this. We'll be looking forward to your updates.