
wow, I am so sorry you're having to go through this.

I too went through this 6 years ago and yes, never saw it coming. My ex told me ON THE PHONE on my way home from work that "he just decided that he didn't love me anymore and he needed to be true to himself." Holy crap. It was like the world fell out from under me. So I know how devastated you must be.
I was very fortunate because I had to great things happen the night he left.
HIS father told me to go online and move all our money into one account in my name only. that way, all house expenses were paid while this was going on. He also told me to change the locks on the house. I did both that night and I'm grateful to him for the advice he gave me.
My best friend went w/ me to the lawyer, which was good because I couldn't hold a thought in my head to save my life. The lawyer told me to keep a journal of expenses.... that when the time came to "split anything" in savings, all expenses paid would come out of that sum first.
Long story short, I had an excellent lawyer. ( he did not) Another thing my lawyer told me to do was NOT give up our computer to him. I thought that was odd until we found all the evidence of what he was doing. Computer dating, etc..... so then we filed under adultery. Well, this lit a fire because he did not want that stigma or me going after his mistress for anything. ( In Mississippi you can charge the person having the affair w/ loss of affection from your spouse...something like that). Well, my ex didn't want his honey dragged into anything. So he gave me a divorce, didn't want any of the savings or the house. He tried to take my dogs but I told him that all bets were off and we were going to court. I've got my dogs.
One thing that's very difficult to do now, but you have to, is keep your wits about you.
Don't fall into the "well he's not like that" or "well, he's being so nice right now". You have to remember, people will do what they have to do. And he's going to do what he has to do....SO MUST YOU. I truly don't mean to sound so pessimistic, but the first thing my lawyer told me was "you never know the person you married until you divorce them". Let me tell you, truer words were never spoken.
Please stay strong......keep paying your bills so that your credit doesn't falter through this process.
Most of all, be a friend to yourself, and know that you are not alone. We all can't be there in person, but we are with you in spirit.