You need better friends lovely, though appreciate that’s not helpful. I am in a very similar situation, husband of 23 years having an affair - fucked right off without a backwards glance, moved in with the affair partner (15years younger than me) 150 miles away. He’s been gone 10/11 weeks?
My son is an amazing support (similar age to yours) and has no time for his dad due to his behaviour. I’ve tried to keep my upset from him but that’s not always been possible.
Like you I’m devastated. I thought we were happy, we were making plans for downsizing and travelling a bit once youngest was at uni, we were still together in every sense of the word and in moments he’d taken everything from me. The person I loved, my family, my future and my security, gone. It’s shit. I cry regularly and I just feel sad, I can’t reconcile the person I thought I knew with the callous prick he’s being now, the man I loved, who I thought shared similar values, who had integrity and morals has behaved like he has.
I’ll probably get judged for saying this but I wish he’d died. Now it just feels like I’m mourning someone who is still sadly walking around.
I’m having text communication around the divorce and the kids (birthdays and Christmas) but I’ve put boundaries in, I don’t need texts from him as I’m going to bed for example, so I block his number in the evening. I think you need to stop texting him beyond the basics, he’s not your friend, so what if he’s having a bad day?
I’m also having CBT - my whole world has imploded. I can’t manage this by myself and I need ways to manage my emotions and feelings when they spiral out of control, can you contact your GP?
In terms of Christmas, what does your son want to do? Can you have a lovely breakfast with him then he comes back after lunch?
Its ok to be upset, it’s ok to cry, anyone that tells you differently can fuck off, it’s hideous, it’s painful and you’re grieving for the life you had and the future you thought you had.
Huge love to you x