Based on what you wrote (which I realize is just a limited perspective), your GF does not sound like a very mature, stable person. She's flip-flopping in her position, and not communicating to you clearly what she's thinking. If you look at her whole life, what is the overall pattern? What is her character?
Also, what -- if anything -- does your GF have in common with your XW? Maybe you tend to gravitate towards same type of people....
Me: 50, MLC/WW 45 Young kids Nov 2015: BD1 Apr 2016: BD2 Jan 2017: W filed Feb 2017: D final