Hello! It is truly devastating when this happens - I know first hand.
First things first...tell everyone. I mean everyone....don't keep this a secret. You will find friends, new friends, in the most unexpected places. They will be your life line. I didn't tell a soul for ten days and suffered hugely for it. Once I did, how people rallied around was awe-inspiring.
You're not going to get over 22 years in a heartbeat, and you're going to be harking back to happier times and pondering "why?" and "what could/should I have done differently?"' You're also going to speak many an angst ridden hour wondering what's wrong with you.
The BEST advice I ever came across was: There's nothing wrong with you, what's wrong is what's happened to you". I read it here on MN, and it's true.
There's plenty wrong with a person who simply walks out without a backward glance.
There's zero, and I mean this, zero point asking him why. You'll be gaslighted, lied to, personally attacked and left even more perplexed if you do. As best you can get contact down to a minimum...dates/times for collecting the children. That's all. Never answer an email/text in the first 24 hours unless you have to.
Your self-esteem is obliterated but they'll have been eroding it for a long time before you realised. Do absolutely anything you can think of to repair it. I did courses (including Women's Aid Freedom programme) I learnt to drive, and got counselling and I talked and talked and talked.
You're going to feel physical pain, struggle with coping for more than 5 mins at a time, lose a stack of weight, and suffer with vivid dreams and disrupted sleep. "This too shall pass" is a good mantra. Eat little and often. Ice-cream, mushy food, chocolate whatever. Don't drown yourself in a vat of wine (I did!)
I truly would not wish this on anyone, I always believed that people who divorce "saw it coming" or somehow made a decision together. I didn't.
The only self-help book I found useful (and believe me I read a lot) was Runaway Husbands by Vicky Stark. The emphasis is on you, not him, as indeed it should be.
Someone on here will be able to help you sort out child maintenance, tax credits etc because it's not unusual to get cut off financially: adding insult to injury!
There's no miracle cure for a broken heart at all. But long after the event, what women I know this happened to regret most is having begged. So don't beg. As someone said above: pretend to all intents and purposes you are managing fine with out him.
None of the women I met along the way believed we would survive it, but we mostly have. The hardest time is about four to six months after he left, when friends and family have gotten used to it - you, of course, are just starting to face up to the reality of it. Depression really kicks in then. Get counselling/take meds/do whatever you can to get through each day. Usually the divorce starts about then too....
I have recently been diagnosed with PTSD. This is 3 years after he left (May 2014) and a brutal divorce which finish ten months later. Four court appearances just about finished me off. I never knew the man I married. So I for one do not underestimate just how shocking an event this is.
That said, my life is very different now. I can see he and I were very dysfunctional. I am glad he's out of my life - despite rearing his ugly head here and there, I am starting to feel happy again. I have a new sense of freedom, great friends and hope for the future has returned. I laugh A LOT. I have hobbies again. A social life. I'm settled in my home. I truly believed my life was over when he left. I was very wrong about that - it's just the biggest nemesis is time.
You will heal.