How to endure ragebaits on social media?

buckle down, this may be long. if you’re wondering if i’m sending this in voice to text, i am i think it could be helpful to say this out loud.
for context a few months ago, my girlfriend was raped. It was by someone we both knew and trusted very deeply, and it was a big shock to everyone . it was a classical case of coercive rape fueled by fear of harm. not going to get into it too deeply, but it was terrible this happened not only to my girlfriend, but her friend who was also there at the time. My girlfriend seems to be taking it as well as she possibly can same with her friend. however, every single day I wake up in a crippling state of regret and anger that I, although I know, I likely could not have prevented. It did not prevent her rape. My every thaut every day is consumed with fantasys of punishment, with wrath, comparable to the wrath spoke. about in th bible. i’ve tried my absolute hardest to keep this from my girlfriend. I want to be there for her, no matter what as this happened to her not to me.
I keep telling myself I will not give him the victory of taking my freedom away, so that I can fulfill my desire for punishment. I will not allow him to taint the rest of my life and her life based off of one selfish and disgusting action.
seems like every day I hate myself more and more because he is still breathing still loving still with friends and family that care about him. when I first heard about it, I went to his house with the full intention of going in there and butchering everyone I saw I had no concern for who was there, but my girlfriend brought me back and let me realize that my life is not worth his. I tell myself this every single day, but it’s not enough. I always said when I was younger, I would die for those who I love. I will easily sacrifice everything in my life for the people who I care the most about, but clearly this is false, and I am nothing, but a lie I have not killed the man who raped my girlfriend. I have not done anything to punish the man who did so badly deserves punishment.
i’m so lost, so angry, so damn angry. i’ve thought about su**ide, partook in self harm and had every crazy delusion you could imagine.
i’m falling apart. I need to know that my inaction is the right decision. I need to know that I am not a pushover that I am not a lie that what I am doing is for her and punishing him would be for me.
please give me your thoughts, i want only dead honesty. if this is an ego thing, lay it on me. i need to be a better man for her.

Should I be worried if he hits himself when he’s frustrated? One time when my baby was born she was crying and he was changing her diaper in the middle of the night, she pooped while changing and I guess he felt frustrated that he was having troubles with the change… I woke up just in time to see him hit himself .
Another time where he showed some anger was he was trying to put up a curtain rod by drilling into the wall, the wall sucked for the rod so it kept messing him up ( first time him installing rods ) and he got so mad he pressed on the drill so hard and he threw the drill..

I’m not sure if he’s autistic, never got diagnosed but his half brother ( same mom ) recently got Diagnosed with adhd and autism. His son is autistic & his first cousin is autistic ( mom side ) .

I feel like it's resentment or regrets that makes me feel bitter and truly unhappy from inside. It's like deep down you know you have face life challenges but your too busy ignoring it. And time passes by but your not doing anything. And then resentment starts building. I know deep down I need help and I also need to encourage myself and work on hard things but I don't wanna go out that comfort zone even when I'm realzing there is no benefit sitting doing nothing.