My understanding is that you validate feelings, not actions or opinions. This is particularly important with women as they process their feelings/thoughts by talking about them. When you validate their feelings, it allows them to process them instead of having to stop and defend them, which reinforces them. Same applies when dealing with children.
How and when you confront their behavior, conclusions, depends on where you/they are in the relationship and your goals.
In other words, "I understand that you were feeling ignored, unloved, etc.," not "No wonder you had an affair, you poor thing." Being able to get past validating feelings in order to deal with actual issues is the tricky part. John Gray suggests that in the ordinary course of a relationship couples should be clear as to whether they are discussing feelings or trying to address issues. I think it gets much more complicated once you reach the point of a WAS.
