Of all the divorced couples I know it’s the ones who are on friendlier terms that the children are doing better. My very good friend (a man) divorced his wife (after she cheated) ten years ago. He won’t mention her name. His family never speak of her and he has very much done the grey rock technique. They don’t verbally speak - just text. He is an extremely kind, intelligent man who I think was hurt immensely, his way of dealing with it was to cut her off, have minimal contact with the ex, only refers to her as the ‘children’s mother’ and has closed off that chapter. But the kids are monumentally damaged. They were bubbly fun children, after the trauma of the divorce, my god they changed.
Another couple I know from school who are recently divorced, stand at sports day, not talking, to each other, both doing their best to fawn over the children. But it looks ridiculous. They’d look better, passing the time of day, chatting about the weather, the odd smile.
And I have another friend, who changes up husbands fairly frequently. She’s on good terms with most of them and their families and the kids seem well adjusted, despite the eldest two having lived with three different men by 15. I’ve always thought her attitude was very blasé but I don’t know, she’s got no beef with the husbands and all the kids seem happy enough.
I know you’re protecting yourself OP and your behaviour is very dignified, but in time it may be better to let go a little bit. Maybe draw a line under the divorce and loosen the reigns on your anger, but be very careful not to let him in again. It’s early days. He sounds an arrogant swine and no doubt will have someone else in time.