Often I feel second place. They have plans to move apart soon, but the actions that would lead to this move are not being accomplished. By the way, we have no commitment, but seem to be very serious. Many women have a very hard time letting go and actually ending a relationship. Your girlfriend is probably stuck in the patterns that she and her ex established long ago, and may not realize it.
Separation is critical to the ending of a relationship, even though it is initially painful.
Your girlfriend is avoiding that separation pain, but it appears to be at the expense of her relationship with you. I want to encourage you to sit with yourself and work to figure out what it is that you want from this relationship. Once you have done that, and you feel you can keep that clear in your mind, then I think you need to have a very frank discussion with your girlfriend about how you feel about her, how you feel when she slips into her other relationship pattern with her ex, and what you want from your relationship with her. I am not suggesting that you pose an ultimatum, unless that is what you want, but that you lay out your feelings clearly for her to see and ask her to tell you how she feels and what she wants from your relationship. Hopefully this will lead to some negotiation about how each of you can get what you need from your relationship, and how your relationship fits into the overall framework of each of your lives.