You are getting great advice, please breathe, relax, and try to process without focusing in on worst case outcomes. To me, you have an opportunity here to show her that you have become the man she wants, not possessive or dominating.
I have asked this before, not sure you have answered. Have you guys gone to MC? We found an MC who was trained by MWD and Gottmann and was very pro-marriage. Gave us a safe place to have these types of discussions in a non-threatening way.
CB
Me; 42, W; 43 M; 16 yrs S12, D9
3/13 - "I want to move to XYZ City (four hours away) and it might be without you, not sure" 5/13 - "Not sure I meant that"