In addition to stresses associated with changes in the family's circumstances, one of the most important sources of problems for both boys and girls undergoing a family divorce is thought to be

a reduction of warmth, support, and structure provided by the custodial parent

Explanation:

When two parents raise children together they form a structure that is binded by two people who offer the same love and support to their children and children get familiar with this structure that is balanced by two people.

When this is distracted a parent who is given the right by the court to take the children won't afford to keep up with the same structure and children start to feel less support and warmth and mostly because one parent has to now take care of everything in the house which may be too overwhelming in such that the children may start to feel neglected.