When the adulterous ex-husband is still angry

15 months post-divorce, I find myself and my ex-husband in a very different situation from the self-reflection offered in this video. He had the affair, but post-divorce, is filled with hostility toward me. I am indifferent, but cordial, toward him as I am relieved to no longer be burdened by the chaos of his choices. I am sad for him and my children, because our children want little to do with him, and he rarely tries to see them. I'm sure he blames me for the consequences of his choices. His pride and narcissism will likely prevent him from ever fully engaging in acknowledging his poor decision-making, much less attempting to make amends. He seems to spend his days trying to figure out how to cut financial support for me and my children, but spends on himself and his affair partner endlessly. I am interested in the psychology of such people, but recognize that I may never fully understand. Thank you.