tug of love       
noun [ S ] UK informal uk/ˌtʌɡ əv ˈlʌv/ us/ˌtʌɡ əv ˈlʌv/
 (尤指报章用语)监护权的争夺,“夺子战争”
used, especially in newspapers, to refer to a situation in which one of the separated parents of a child takes care of the child but the other parent claims that right, or a situation in which a child is being taken care of by people other than the child's parents but the parents claim that right
  [ before noun ] a tug-of-love battle 夺子战争