DH threw a tantrum and so I'm taking a pause

Ask someone in the family to look after the DC for one night and you go with husband to the hotel or during the day for a spa, as you both seem in need of time together.

He may find your way of correcting the children a bit difficult, so he feel more stressed than a straightforward clear way of speaking.

I would communicate with him about the fact you are going to a hotel.
I would hate to come back to an empty house and find my family gone with no explanation.
Also, it's not talked about much, but 1 in 10 men experience post partem depression.
I would first have a conversation with him. My husband and I talk about everything that we feel we need to. Maybe he doesn't realise how he is behaving.

Having said all of this, you are the one who is in the situation and not one of these posters on this thread understands or knows your situation. If you feel unsafe you need to do what you feel is best.

Her baby wakes up every 2 hours. Why on earth should her husband not do at least one of the wake ups. She must be exhausted. Why do women think that men shouldn’t do wake ups and women should be absolutely exhausted doing school runs house work and looking after a baby. It’s not like she is sitting around all day able t sleep.

Leaving with the kids without even having a conversation is escalating this and an overreaction

Maybe. I feel like it was actually quite mixed.

Personally I think leaving the house without even discussing it is a exaggeration .
Maybe he feels overwhelmed and feels you where calling him lazy ? If you are saying he is not , if he cares for the girls and goes to work while you give more if your attention to the baby then doesn’t come across that way .
Aren’t you better sitting down together and talking about his behaviour and loss of patience and about expectations from both parts ? I mean abandon the house comes across as you already given up .

When I was on maternity I did the nights. Weekends DP did. I didn't expect him to get up with DD in the night if he was the one going to work the next day and me staying home.

I think your sister has been very foolish, wading into a marriage with a snap judgement.
It sounds like you both are stressed and tired. Maybe just take a beat, get child care, and spend some quiet time with each other.
I totally understand about emotional unregulation, and I find it unbearable personally, but in this case there may be reasons why.

I get the impression that the answers didn’t go her way, so she made it bigger in the second post.

I got the impression that OP was downplaying it in the first post and clarified that it was worse in the second post which is why she said she was clarifying some things.

I do not think it is in any way normal for a child to be driven on an almost daily basis to tears by a parents anger.

Thats scary stuff.
I hadn't the greatest of patience at all times but to be so angry that your 6 year old crys almost daily?

Something very wrong there.
Not even one lie in?
Night after night?
Selfish.

I think you taking time away is even more rest for him.
How nice.
No wonder you are haggard.
Two children and an angry man child.
You need to mind yourself OP.

Your posts are miles apart from each other, so I'm not sure what you want people to say.

The first post and the second post did not say the same story, me is true the other isn’t.

We don’t know which is which.

An OP is allowed to add further details of what they see as a problem. It doesn't mean their first post was a lie.

Clarrifiacation to that last post: the OP never said crying everyday in the OP, which was the only details present when the abuse comment was made. That was added after the interaction that the previous poster commented on.

"I often found him growling or yelling at DD1... it felt like though he'd never fully yell at her it was always raised voices and irrelevant threats and punishments. Just the opposite of all gentle parenting guidelines. "

You have managed to reply to something that was neither in my post, or the OPs.

She never said that he yelled and made the daughter cry everyday.

And I never said that yelling and making kids cry everyday is normal.

So what exactly are you replying to?

I think that was a thoughtful update OP

And the poor child is then probably really confused therefore leading to behaviour problems as they are getting mixed messages.

His yelling makes DD1 cry on an almost daily basis.

No parent should be yelling at a child on a daily basis. That’s abusive.

He needs to reflect and learn parents don’t yell at kids. Any more than they should yell at adults. I’m sure he manages not to yell at his boss or work colleagues. Or (hopefully) you. So he can certainly regulate himself enough to avoid yelling, e.g. when stressed. He simply chooses not to with your DD.

He needs to ask himself why. Has he been brought up to learn naughty kids are yelled at? Or to think it’s OK for parents to vent their frustration aggressively to kids and not adults?

Does he want his kids to learn this too, through his example? And potentially repeat a pattern?

Maybe the OP can clarify but that does not sound like "behavioural problems" just that they've agreed on a strategy for managing her behaviour. Because 6 year olds misbehave sometimes without having "behavioural problems".

It isn't something I'd accept personally but like you said, everyone is different.

I feel like your kicking/throwing examples are different to when it is combined with someone shouting and swearing at you. That feels much more aggressive and can be abusive.

Just the opposite of all gentle parenting guidelines. I've tried to sort this with creating written house rules we both agreed on to help DD1's behaviour, thereby removing the need for arguments or silly uses of no screen time etc.

So OP knows there is behaviour problems but instead of letting him parent his way when he is in charge of DD1, she has implemented gentle parenting "house rules" that he is expected to follow to combat these behavioural issues.

It actually sounds like when he is trying to implement any sort of discipline DD1 is either arguing with him or it is resulting in her crying (not really surprising if DD is used to getting her own way), and because OP doesn't agree with discipline of any kind, as it goes against the gentle parenting handbook, she is stepping in at that point to undermine it leading to frustration on his part and resentment for them both from the sounds of it.

He doesn't think her way is paying off and she won't let him parent the way he wants to, so it is unknown if it would be better for their DD or not.. Either way parenting should really be collaborative, not one demanding the other follow their "rules".

Neither is it for some adults to do it under stress either! We’re all different. Labelling every reaction as abusive is ridiculous.

DH and I have both used swear words in arguments with each other. We’re adults as can handle adult language. Once I kicked the hoover when it spat out grit onto my new rug. Another time I threw a cushion onto the bed. No one is traumatised.

Sorry, where does it say that their daughter has behavioural problems?

I've never kicked something in frustration or anger and DH hasn't either. I really don't think it's that unusual.

Raised voice? Of course.
Swearing about a frustrating situation/stress/bad day? Absolutely.
Swearing at each other? No and I wouldn't stand for it either.
Growling at a child enough that your partner is concerned? No.

Again, I really don't think any of that is unusual.