At no point has he shown any empathy or sympathy for YOU. Or desire to be with you or regret he's left you. It's not you he wants - it's the kids. You have been well and truly cast aside for someone who made him feel like the hero in his own story. Like they admired and adored him and saw him as this fantastic wonderful man and he's got carried away with that and believes the hype.
He thinks he lives in the rental. Sees the kids 50/50 and after a 'decent' period of time elapses introduces them to the OW (who has been told you are a boring, sexless shrew) And its all great. He gets to be happy and see his kids loads but not for the boring bits like dentists appts etc and eventually everyone will forget you exist. Gets to be with her. And you can just do whatever it is that boring ex wives you no longer want (therefore no one else does) do. Like take up crochet or whatever.
That's his plan and you constantly talking about OW has scuppered it somewhat. People have been quick to defend him, oh no he's not that kind of man! But he is and he knows it. And it's brought it to peoples attention so it is a lot harder to just suddenly 'meet' this shiny new woman. He has to back off for a while as his precious reputation will be shattered.
He won't engage in conversations about it. Because he's got the perfect right to leave you as he's no longer in love but they are his children too and do he has the right to spend time with them and they will understand eventually.
That's what is in his mind. All you can do now is look after you. If he wants contact you facilitate that but you make it convenient for YOU. And that means no fucking spare room!
You have split up and that takes dealing with but I promise you he wasn't the happy husband you thought, far from it. The second someone came along that made him feel sexy and like a hero he went and even if he wants to come back hes doing it purely for a nice house, his kids, and to have the convenience of being looked after.
You do not have to make his life anything - you have your own broken heart and those of your kids to deal with. He will do anything to make it up to them but you personally will get nothing out of him. So as with all break ups you need to have no direct contact and certainly not spend time with him.