I am sad to see her go, but she needs to do what is right for her. As we have seen, most people that get the heave ho don't give a sign off, so I must presume based on history that she did indeed make this choice on her own.
Who knows if her husband's job changed or his hours were changing; maybe she "had it up to here" with her own schedule. I grew up in a household with someone who worked shift work and nights, and it was challenging for everyone because of their sleep schedule, their daily work schedule, missing family or school events, etc. Working at QVC and still being "newer", she still got pretty terrible working hours at night and maybe she was hoping they would adjust over time, but I see the newbies are on far more often during the day on Q2 than Stacy.
I wish her the best in whatever the future holds for her.