It is in human nature to seek security. Once a relationship is formed, an individual may become overly anxious that it will end or be too weakened. Therefore a departure, such as a partner working overseas, or a son leaving for university, may set up anxiety in the one to be left behind. However, clinging on rarely works.
Even if it results in a person staying, when entreated to do so, it will be with resentment and consequent loss of the love that had gone before. Nothing is simple, however, for the generous person who 'lets go' may be seen as not caring enough. "You never stopped me going" can be the complaint as much as "You wouldn't let me go". Oh, if Life were simpler!