Husband lost his temper and bruised our child's arm

[Babibel]

It's not the first time. It's the 4-5th times over 4 years. Our child can go very far when he is hungry or misunderstood. He kicked his dad in the bus, spat, said bad words. I advised his dad to try to talk about something my son likes, or change seat, or stand next to him, etc...Instead husband sat like a stone, being kicked and he ended up grabbing him very hard to the point that my son has bruises on his little arms. I can understand grabbing, I can not understand squeezing this hard. I was not there, I just saw the results when they came home.
He loves his son but, this happens. (Me, I am abused mentally, but that's another topic).
Thoughts?

And also going from ignoring it for ages then straight to physical violence is another red flag, he went from 0-100. That's not how you parent, he's acting in anger.

Save up. Buy a plane ticket and leave. Make a record of everything.
Take your child to a doctor because he may have developmental issues.

H says that I "made him this way". He says that he was a happy person before he met me. He claims that I was never happy in his country and this is why everything went to hell. (I was never happy in his country and I tried to move out many times unsuccessfully). Now I am fully ready to move away

Gaslighting

Your husband is abusing you and your son, physically and emotionally. You need to take steps to leave him. Contact Women's Aid for advice if necessary. You need to get away from him, with your son, before you start trying to leave the UK.

I suspect your son behaves the way he does because, as you say, he has grown up around a man who is aggressive and abusive and has a temper. He probably has a lot of resentment towards his father.

We don't live in the UK, as mentioned earlier, we live in Europe. (In my heart UK is still in Europe, don't get me wrong, I love the UK).

We need to be very careful about potential advising the OP to commit intermational abduction.

Also we can't say if the actions are illegal as we don't know the country she currently resides in.

Your husband sounds horrible. I hope you do find the strength to leave him.

I think you will also need support to manage your child's behaviour after you move away (which it sounds like you are planning to do).

My stepdaughter was incredibly violent a few years ago - similar age, similar behaviours. She'd grown up around an abusive alcoholic mother (now deceased). It's taken a lot of calm and stability to get her calmed down and stabilised. My husband found it really difficult for a while, to cope with her.

Leaving will not be a magic cure, but I hope you can find the support you need to build a better life for yourself and your son.

So this is the fourth or fifth time that he’s injured your child and you are still with him. You need reporting to the Police and children’s social care, as does your partner. You are failing in your duty to protect your child. Disgraceful.

OP, do NOT just take your child to your country without consent as some people are suggesting. That is kidnap and you could be forced to return your child to his father, out of your custody.

You must document everything and take advice from a lawyer. Try to find a women's charity that will help you with some free legal advice. But your priority must be keeping custody of your son, primarily so everything has to be above the law.