[Toria]

There could be other contributing factors to her behavior, not just another romantic interest. When does she defend her thesis? Is she behind in her research? Does she have a committee member that is disagreeable or not supporting her research decisions? What are her plans after she finishes graduate school?

At the end of a long academic road (I have been there) there are a lot of questions about who you are actually becoming and where you will fit into life. You have finally become the person you have been molding yourself into for many, many years. Who you are when starting an advanced degree is not who you become over the course of obtaining it. An entirely different person walks out of commencement compared to the one who walked in the first day of the program.

My point, it does not have to be another person, it might just be where she is in her own life. If you want to stay with her, you need to have patience and give her space to become comfortable with who she has matured into. She cannot be anything to you if she is not satisfied and comfortable in her own life. Sometimes support needs to be in the form of silence.

If it is another person, I am sorry. You will hurt regardless and will need to find a way to move on.