    A Broken Mirror Made Whole Agian 破镜重圆

    In the Northern and Southern Dynasties when the State of Chen (A.D. 557-589) was facing its demise, Xu Deyan, husband of the princess, broke a bronze mirror into halves. Each of them kept a half as tokens in case they were separated. Soon afterwards, they did lose touch with each other, but the two halves of the mirror enabled them to be reunited.
  南朝陈国(公元557-589)将要灭亡的时候，驸马徐德言把一面铜镜破开，跟妻子各留下一半。双方约定：如果将来夫妻失散了，就把它当作信物。后来，夫妻二人真的失散了，凭借着各人留下的半面镜子，他们最终又得到团圆。

   This idiom is used to refer to the reunion of a couple after they lose touch or break up.
   "破镜重圆"这个成语比喻夫妻失散或分离后重新团聚。