It's always a nice idea to think that you and your ex-wife will go through a divorce and one day be able to work together to co-parent your children. And while for many this may be true, the truth is that in some situations your ex-spouse will continue to be hostile well after a divorce and make it difficult for you to deal with their antics and raise your children together.
In these types of situations it is quite common for an angry ex-spouse to even go as far as to convince themselves that you are not a good parent. And while this could be very far from the truth, in many situations the hostile ex-spouse is also trying to portray this image on others -- like doctors and school staff -- and sadly, in some cases, even the children.
When this happens, and it is just not possible to reason or have a conversation without it turning into an argument, one suggestion is instead of co-parenting to try what is called parallel parenting.
With parallel parenting, both parents still play active roles in their children's lives, but communication between both parents is limited with very clear expectations and boundaries. For example, if talking on a phone always leads to an argument, the best thing to do is only have communication over e-mail and text messaging. This way, negative comments can be deleted and there is time to think of how to respond instead of just saying the first thing that comes to mind after a particularly nasty comment.
However, while with parallel parenting communication is limited between parents, it is up to the non-hostile parent to be proactive and reach out to school staff and doctors. This will give the parent the chance to explain the true situation and demonstrate that he or she is a competent and caring parent. At this point, it's also even a good idea to provide these people with a copy of a child custody agreement to let them get a real understanding of how custody, visitation and decision making actually works.
In the end, in situations where a divorce leads to hostile parents, it's best to try parallel parenting in order to provide mental sanity not only to both parents, but to also keep the child out of the middle of the situation.