Well no I can't imagine that could be it because of how SO in love we were and the fact that all the feelings started to diminish in coincidence with her escalating depression. If she did not have depression then I could entertain that, I would surely then have seen the symptoms of falling out of love, and had some semi rational conversations about wanting different things etc and there being some evidence of this, but with this, everything went from loving each other, demonstrating deep love and understanding with each other, sharing joy and happiness together, to panic attacks, increasing in frequency, anxiety related stress, panic and depression, feeling of 'drifting', feelings of having lost herself, feelings of numbness, to the conclusion that a numb and feelingless state equals not being in love with the love of your life any more and they deserve better and could be finding some one else.
That just doesn't seem like a normal break up situation to me...