I don't know how to let go...

Constantly Wills dad makes decisions that I can't fathom about Will. I don't pretend to understand the reasons, I know from a person outside his brain the reasons seem selfish and totally self serving. I am trying to see another side to the story. I know there are always 2 sides right? But even his explanations don't make sense to me. They still seem self serving to me. Am I too rigid? Maybe.....I don't know.

Over the years I've been told, and again today, that I can't control what he does--true-- so I need to "let it go" and "not let it bother me". How do I do this when what makes me so angry and leaves me feeling so helpless is the knowledge that WILL is the one that pays the price. He is the one who becomes so overwhelmed, overstimulated, overtired etc and them has to take another hit to his self esteem when he has a melt down (usually, but not always, on my end of the week- sometimes resulting in violence towards me) which makes him feel bad about himself and reinforcing his negative thoughts and self talk.

Yes, I usually deal wit the fall out and yes, there is resentment over that. However it is 95% about Will. What he needs, what he does and doesn't get and how it affects him.

Am I overreacting? I'd his dad really being selfish? Am I so rigid in my thinking that I can't see it any other way but mine? I really don't know....but either way- how do I let it NOT bother me so I'm not eaten up inside all the time?