从未想过绝望看他走
[cóng wèi xiăng guò jué wàng kàn tā zŏu]
This idiom-like phrase,"Never Thought of Desperation While Watching Him Walk Away", is about a state after break-up or departure when one tries hard to hide the pain by saying they didn't care or were prepared for this all along. But factually speaking, this attitude stems from the unwillingness to lose something precious but helplessly.