OP, I’ve been following your thread since you started the original one and although I’ve not posted any advice previously, I just wanted to urge you to please not give up on your own life and your recovery through this awful, shitty situation you find yourself in.
My dad did exactly the same to my lovely mum. After 28 years of happy marriage, he came home one day and calmly informed her that he was leaving her, had met someone else and he wasn’t coming back. She was absolutely blindsided - had no idea anything like this was coming and had no way of coping with it. She blindly clung to the hope that one day, he would come back but sadly he never did.
Mum ended up in a one bedroom flat. I was a young adult at the time, with a husband and a baby but I saw her every day and did my best to look out for her. Despite encouragement, she couldn’t move on. Her health suffered. She refused to go out and stopped engaging with everyone apart from me. She talked about dad endlessly and waited for the day when he’d come back with his tail between his legs and love her again.
Ten years later, she died. She’s given up on life as she said that she had no life without him.
Please don’t let this happen to you. I don’t know how old you are - and I totally understand the pain you’re in but you must, a little at a time, start to heal. Yes, it will take a long time, it’s worse than a bereavement because he hasn’t died - which would be outside of his control - but has chosen to walk away. But you must try and carry on - for the sake of your children and other people who love and care about you.
I was heartbroken when my mum died, and I didn’t speak to my dad for 10 years. He’d cast her off like shit on his shoe, cared nothing for the woman who had been a good and loving wife to him for nearly three decades, because he was a selfish prick who only thought of his own wants and needs. Funnily enough - he’s 91 now and I know full well he regrets what’s he’s done. There’s only me to look after him and although I do, on a daily basis, I do it out of duty and not love - he doesn’t deserve that.
Take it one hour at a time for as long as you have to but please don’t give up. You CAN and will find peace and happiness again but you have to let yourself be open to that. Don’t spend years pining for someone that could treat you so utterly poorly. Don’t throw the rest of your life away like my poor mum did.