If you didn't react to the 'old' comment, that's probably what the tantrum was about. Prod, poke, goad - nothing. It's mummy, mummy, mummy .... waaaaaaahhhhhhh.
This is not an adult man's response to a situation.
He certainly seems to have stalled in childhood/adolescence. The gross behaviour, the stropping, the demands to be serviced, the disappearing to his room for hours on end.
I wonder what kind of upbringing he had? Is there a mess there, too (as you've mentioned yours was)?
I think it's time for an adult conversation.
Calmly set out the points you've made here to us (hope you've found this a helpful notepad for getting your thoughts out and ordered) about:
his physical unpleasantness
his sexual behaviour
his verbal abuse including the terms he chose to use
His insults
Everything that he has exposed the children to
His obsession with childish computer games
His inability to parent his own children
And tell him you agree it would be best to do as he suggested and for him to spend Christmas with his family.
You're panicking now. Going down the same route so many here wish their mothers hadn't taken. Staying together 'for the sake of the children'. What if what if what if.
Yes, he might say he's going for 50/50. They are his kids, too. They often do this, for control of you all. The fact you're the breadwinner and he's on the face of it their carer may well be a factor.
He has no idea what that means, though - and the reality of it would probably make him back off and hand responsibility back to you.
I think some real world experience of being separated could be beneficial. Help you all get used to a new way of life.
Otherwise - you have decades more of this ahead of you, and they only get more like themselves with age. Then the children will be gone, having observed what he did, what you put up with, as their role models, living their own lives and you'll be staring at him wondering what if I'd done the difficult thing and created a different life, a different path.
Get some professional legal and financial advice and step aside from the panic reaction and start thinking clearly.