I do hope that the OP is still reading, and getting strength from all of your experiences. She probably is a bit shocked, but it takes a while to wake up in these situations. (Been there too, but no pet involved, thankfully.)

Hopefully you have helped to push her a bit closer to realising the reality of her relationship. At least, you have hopefully strengthened her resolve to protect the puppy from further abuse.

Keep talking to her in the hope she's listening. She could do with some Dogsey support to get through this.

I was in the bad books with my wife for a bit when I got a 2nd dog..

Sounds to me like your OH does not want a dog. I would suggest talking about it, explain that the puppy is still very young and really does not know any better and the situation will improve. Explain that beating or terrifying it will cause problems for the dog so would he agree not to? Maybe if you say that you will give it up if that is what he wants then he will say no, that he wants you to have it. That way he will feel like he is still the most important thing in your life. Then plan and agree what you will do in future and plan for different scenarios . That way you will be a team instead of being caught unaware and fighting. Communication is key I think

One other thing, unfortunately the majority of us men are far less mature than you ladies. On reading your later posts, I would say he is angry about something else in life. A happy person does not sweat a 4 month puppy unfortunately.