I'm not a very angry person, I don't really have it in me to be genuinely pissed most of the time. Sometimes I'll get irritated, and I can usually kinda DBT my way through it, but honestly I'm really pissed at my ex. The more I think about everything horrible she did and continues doing, the more I kinda spiral into being pissed and it's not helping me at all but I don't really know how to decompress all of it. I'm rightfully pissed, she did some truly nuclear shit I'd need content warnings for, and having that anger is healthy at some level. But like I said, I need to get my mind off this shit so I don't become a bitter divorced dad lol
I think it helps to forgive yourself for your mistakes and shortcomings. Forgiveness in the sense of coming to an understanding that you are not perfect or omniscient, and that you can and should still lead a life of meaning and happiness outside of the past grievances, or understanding that you should, because of them.
Your ex, your abusive parent, sibling, boss, or friend have come and gone and the scars and wounds are remnants of those times but they don't define you. Forgiving yourself is understanding that you define who you are, and you can choose what you can be. It sounds cliche, but as anyone who has suffered can tell you, anger itself is also just enervating.
There has to be a life beyond a past grievance, fantasy of retribution. Or else you'll be doomed to repeat those mistakes and relive those feelings, because your minds unconscious way of reproducing the traumas in order to overcome them this time around will just remain on loop.
Resentment and anger isn't worthwhile. It isn't cathartic. It isn't vindicating.
What it is, is torture. Forgiveness isn't absolution but transcendence of the pain. So let it go.