I was with my ex for nearly 28 yrs. He left for a 21 yr old married barmaid. Him 52.
Been apart for over a year now.
I don't see any real point in life, on antidepressants, counselling, etc.
My children are my only focus on reality. That and wanting to see the inevitable karma. He has lied and manipulated his family and friends, they will see the truth eventually.
Believe me my ex is delusional, as is your ex.
He needs to work through his dilussion himself. You cannot reason with him, he sees everything from his perspective, and only that.
I hope he treats your children with respect though, that is my biggest bugbear, the way he has treated our children. They no longer care if they have any further contact, which I believe is to their detriment, not his.
From my own experience, however hard it is, have non contact, it achieves nothing and he will distort things against you.
A middle aged man having a personal identity crisis, it is nothing to do you, but his own perception of his own persona, is untenable. They believe they are acting courageously, and fail to see you and your children are collateral damage.
You cannot persuade him otherwise. The more you try, the more they believe they have made the right choice.
Do the best by your children, ignore his infantile behaviour, there will be karma.
I'm here now because of my parents, children's, some really good friends and work colleagues.
Happy to be pm'd if you need to. Not an expert, but a survivor...
Xx