Well, book 8 really threw everybody off! I feel as though this event between Andrew, Anatole, and Natasha epitomizes the structure, instability, and scandal of developing marriages in War and Peace. To be honest, I feel as though this could have been easily predicted when looking at other relationships that have been formed throughout the book. Pierre, another classic example of marriage so far in War and Peace, blindly "falls in love" with Helene, and it eventually backfires on him. His immaturity, the manipulation of the family involved, and the speed of events that occurred all lead to his ultimate unhappiness.
This directly parallels with Natasha. After being "vaguely interested" in Anatole, Natasha begins her downward spiral, just as Pierre experienced. Her blindness to the future and rapid development of "love" with him eventually leads to attempted self-harm and complete unhappiness. It was also a very irresponsible act that didn't take into consideration the feelings of Prince Andrew. Albeit, he mentioned that she could cut their engagement at any point, she did so in a way that could seriously due emotional damage to an already instable Andrew.