Seems to me like she's very emotional right now and very torn, and has a lot of self-pity and guilt. Maybe she feels that going through the finality of divorce is a way out of her emotional turmoil.
First, I would back way off. Just give her time and space.
I would prolong it as long as you can. If she wants divorce (assuming you don't), then let her do all the work. I wouldn't even talk about it, as long as she understands that you don't want divorce. If she's not sure of your stance, then you can make it clear to her next time she brings it up.
M: 15 years BD: 6/25/14 EA/PA: starts 5/14/14 11/30/14 - A ends 5/15/15 - D is finalized. 11/28/15 - Start of new LTR with a wonderful woman (and still going strong)!
