He throws things and breaks them to show you just how much he wants to break you. I'm sorry, but he doesn't need to learn how to 'manage' his anger. He's doing that right now. He's using it to manage you; to frighten you, to cow you and to control you.
Are you finding yourself tiptoeing around him? Walking on eggshells dreading the next outburst? Hushing the children so they don't set him off? Picking your moment to raise difficult questions with him because you fear he'll go off the deep end?
You're being abused here. And when he frightens you or makes you cringe or flinch in case it's you next, that's assault.
What he needs is a perpetrator course to make him look at the origins of his anger; not how he expresses it but why he feels entitled to be angry and give free rein to it. Because every time he throws something or breaks something, it's a choice. He might tell you he loses control but he doesn't. He is totally in control when he does it. If you doubt this, ask yourself these questions:
Does he behave like this everywhere he goes that he meets frustration or difficulty? Does he throw stuff in the supermarket? Does he break stuff at work? Does he terrorise his friends' children when he visits? Does he break his mum's china? What other doors in what other places bear the evidence of his tantrums? If two police officers walked in on him mid-tantrum, would he carry on or stop on the spot? Your answers will show you whether or not he is in full control all the time.
You gave him the ultimatum that it must be the last time. It wasn't. If you don't act, you are teaching him that he can get away with this carry on.
If you can get your hands on a paper or electronic copy of Why Does He Do That? by Lundy Bancroft, please read it. Women's Aid has a telephone helpline and a survivors' forum on their website. If you call the police on 101 and ask to speak to someone with training and expertise in domestic abuse, you will get good advice there, too. You have lots of options and, though it may not feel like it right now, you wield a lot of power, way more than women in your situation ever used to.
Could you ask him to move out for a bit, perhaps to his parents or a relative, once this lockdown finishes on Tuesday? Tell him he must get help to sort himself out if he wants to be with you because a family cannot live like this.
Don't be drawn into saying you'll help him becasue you aren't the expert he needs. You can't fix this problem for him or support him through it. It's his problem, not yours. And couples therapy is not the answer for domestic terrorism - that's for couples who love each other but aren't communicating effectively. He's communicating just fine. It's the message that's the problem.
You're not alone. But right now you're not safe either, and nor are your precious children. You all have a right to be.