Your children are precious. They are impressionable. They are also fragile. You need to do everything possible to protect them, especially when it comes to a fight over their custody. You should never put them in the middle of this fight. It should be kept private as much as possible so they are not emotionally affected by it. But, if they are, they could experience some of the following negative impacts.
A child can become withdrawn during a child custody battle. This can become a big problem if they were very open in the past. When a child becomes withdrawn it could turn into a serious issue where they stop talking to adults, stop sharing their feelings and even become angry with all those around them.
A child might begin acting out at home or at school. Their grades might suffer. They might become violent. It's hard to predict how they will react to a public fight over their custody, which is why it should be kept as private as possible.
Children in the middle of a custody fight could also struggle with anxiety and depression for the rest of their lives. Going through such an emotional issue early in life can wind up scarring them for a long time.
A child custody battle could also cause a child to lose trust in one or both of their parents. They might hear arguments made by their parents that could be disparaging towards each other or even towards the child that results in a loss of trust.
The emotional state of your child can change in an instant when you are fighting for their custody, especially if you are doing it right in front of them. Do your best to keep the custody battle quiet and only between you and the other parent so your child is not affected negatively.