A co-parenting relationship isn't something that is appropriate for all divorced spouses. Instead, these arrangements are best-suited for parents who are able to get along to some degree.
When you are trying to work with your ex to figure out how to raise your children, there are times when coming to an agreement might be difficult. You should do everything in your power to come up with an agreement so that the co-parenting can continue.
You and your ex need to sit down and discuss how the situation is going to work. For example, discuss the house rules at both homes so that parents know the non-negotiable areas. Of course, there are bound to be a few differences between the two households. Knowing what these are ahead of time might help you assist your child in making the needed adjustments when he or she goes back and forth between homes.
Another matter that needs to be discussed is how joint events will be handled. You and your ex need to have an agreement that any issues that must be discussed will be kept quiet until after a shared event. Your child doesn't need his or her parents focusing on a problem instead of the school play.
Make sure that you set united expectations for what family members will be able to do at shared events. For example, family members should know that they can't come to the child's birthday party drunk or they risk being told to leave.
By handling these matters early in the co-parenting relationship, you and your ex can make sure that there is a somewhat united front. This will help to make a difficult parenting arrangement a little easier for everyone involved.
Source: Our Family Wizard, "Reaching Parenting Agreements as Co-Parents," accessed Aug. 18, 2017