Her father's angry reaction not only startled An Qi and left her with her mouth wide open, but it also broke her heart. In fact, she shouldn't have been surprised, as this outcome was only natural.
For many years, Zeng Xuerou and her daughter had always been by An Shijie's side. So, if he had ever needed to make a choice, he had always deferred to them. Hence, it made sense that he would now stand on their side.
But, An Qi did not believe that this could be true until she had just witnessed it herself. She had confronted her father and seen clearly what kind of person Zeng Xuerou really was deep down. Now, it seemed like it was time for to stop struggling against her stepmother's deceit and just simply end the conflict, thus taking the path of least resistance.