LP your choice of language is putting the emphasis the other way round, so that you are biased in favour of the man in this scenario. Is there something here that resonates personally with you, because it's rare to see someone so vehemently defended when he is clearly in the wrong.
All your reasoning points to OP being so difficult to live with that she drives him to desperate measures. Do you think they should be together? Do you think there is hope for this relationship?
What would you advise OP to do.
Look at how you phrase things:
the husband works hard, (agreed)
is a good dad, (women often say this about men that abuse them btw)
(but money is tight so they can only get away for ONE WEEKEND a year (why do you use capitals here?)
the OP then does her best to spoil it - Here it is. The OP does her best to spoil it. Where do you get that from, do you think she did it on purpose. It's just the choice of phrase here that I think stands out.
by blaming him for forgetting shoes using the word 'blame' is, again, inferring that she has done something wrong. We don't actually know the words used, that's all conjecture.
(she's equally responsible) - I agree
So he's worked all year, then loads his daughter into the car, (agreed)
only for the OP to attack him verbally, - Here it is again. You think that she attacked him even though we don't actually know what she said. But you don't think that he attacked her even though we do know he said 'I will punch your face in'.
then be surprised when he retorts. - Here it is again. A threat to punch is not a 'retort'. You are minimising to justify his threat.
And now you are all suggesting hoops for him to jump through - Not sure what you mean here? What do you think people have suggested he do? I know poster have suggested that OP gets more advice, maybe counselling for her, womens aid, see a solicitor even so that she knows what's what if it does come to it, but what have posters suggested he do?
ways he can debase himself at the altar of her perfect womanhood - Here is that strange language again. There's a lot of religion in your comments, btw, not sure if you are aware of that, but no-one has suggested he debase himself. I really cannot see where you are getting this from.
in order for him to be allowed to stay, when he's miserable. Or don't his feelings count as long as SHE is happy?
If he won't do anything to help himself, how can anyone else help him. OP would go to counselling with him but he won't go. He doesn't talk to her about feelings, if you read OP's posts, she didn't even know he was unhappy. The first she knew about it was when he said he wanted a divorce. He has to help himself.
If the roles were reversed, you'd be telling him that one outburst was understandable, and that he needs to leave the controlling bastard who drove him to it.
If the roles were reversed, yes I would be telling him to leave her. If she was behaving like him and he was behaving like her, it would make no difference. Unless they can talk there is no hope for this relationship. They have to separate or stay unhappily married. Of those two options, separation would be the best choice.