Hmm...
There may be an issue here.
Sometimes it's ourselves we have to check. If you find yourself explaining to someone why obviously scary/upsetting behaviour is such... it's not a good sign.
And now you're even being the one to research FOR him on how he can be better.
Men know shouting around women is scary. They might forget it in the heat of the moment but when you called him on it he should have straight up apologised without you having to explain something obvious to him first.
That would have me on my guard.
It's good that he claims to understand now but...
Just be careful not to get into a cycle of thinking 'I have to explain why xyz is bad or hurtful. If I find the right words, he will understand'. Because that can go bad really fast. You can end up thinking you are in the wrong if you 'just can't seem to find the right words to make him understand'.
And now here you are on research mode for those right words.
Men are not children. We do not need to inphantalise them. We are also not their therapists. Or their mothers. Or...their own inner conscience.
Don't get into the habit of walking him through basic human empathy. He has it or he doesn't.
You've made him aware of the issue now. It's up to him to do better. If he doesn't, leave.
And certainly be on your guard now moving forwards just incase.