I spent years dealing with simmering, and sometimes raging, anger. What a waste! I knew it was debilitating but try as I might, I failed for many years to extract myself from its grip. I often held onto the belief that some action on my part toward my antagonist would ultimately provide cathartic release. It didn't work that way for me.
Ultimately the passage of time, active reframing of past events, and genuine forgivenes allowed me to move on. It was one of life's hardest lessons!
Anger is corrosive to the person who feels it. The person at the focal point of your anger has no sense or care of your pain. The sooner you spend energy and attention elsewhere, the better off you'll be.
I found forgiveness provides the antidote to anger. Forgiveness is a willful action that provides release to the forgiver, not the forgiven. Your antagonist may not deserve forgiveness, but you do!