This often manifests itself in nitpicking about how the other parent spends their time with the children. Specifically, many parents have trouble knowing that their children have been left in the care of an extended family member or a babysitter, when the children could have been spending time with them instead. A solution for this is to include a right of first option for childcare, also known as a right of first refusal, in your custody and visitation order.
If you have a right of first refusal in your custody and visitation order, then when the other party requires childcare for an extended period of time, they are required to ask you first. The length of time is typically around 4 hours, but the parties can agree to any length of time. So, this wouldn't apply to trips to the grocery store, but it could apply to picking up an extra shift at work. When stepparents are involved, this could also mean that the parent would have to ask the other parent before allowing their spouse to watch the children. This type of arrangement prevents the children from being forced to spend time away from both parents when one is fully available, and can be a good option if you are concerned about these types of long absences of the other parent.