This is a situation we encounter frequently. Family courts and attorneys have developed many tools to help reduce the conflict between parents. This can include restricting communication to be only through email and only regarding the children. In some cases, it may even be advisable to use Propercomm (a service that reviews emails between parents for appropriate content) or Our Family Wizard (an app that includes many tools aimed at helping reduce conflict between parents). It may also be useful to order co-parenting counseling, individual counseling, or have the parents take a high-conflict parenting class.