It's really sad watching these two. With the FL, she has been forced into a life that is equally (if not more) stressful as her previous life in the modern world. She has to learn new things and is expected to be a superior being. All while being burnt out from her previous life.
It also does not help that the ML continues to push her to levels that HE would be comfortable with. He may be the type to think working hard (to the max) is a common mentality, but she has depression and cannot think that way.
I just think with how the two are currently, they are just too different to be a good match. Luckily, he did come to realize that she is struggling and trying to survive the best she can given the circumstances (both environmentally and mentally).