Remembering the Bamboo

Forty years ago, she was a powerful general, and he was a mature and wise strategist. They fought side by side and depended on each other. Once something unexpected happened, the two people who were once so familiar no longer met each other. She gave up the position of general and he became a high official in the palace. From then on, affection turned into suspicion and hatred. The ending is like this, but what is the truth of the story?