Time is of the essence op.
You have to find your fire sweetie, he is up to either polaxing you into grief amd hoping his threats of not loving you will make you accept any behaviour he throws at you or he is seriously thinking of separating and wishes to manipulates the finances to suit him, again you being blindsided with grief will allow him to dominate the situation.
I say this kindly but you have to stop feeling sorry for yourself, whilst you are mourning the loss of your relationship , he is getting one over you.
You must put this to the side whilst you amass any financial information and GET YOURSELF LAWYERED UP.
Pronto!
It does sound as though his head has been turned and he needs to be reminded how that is going to cost him, do not sign anything untill you have had legal advice.
Yes he's riding high at the moment and instead of sharing his success he has betrayed you, financially, emotionally and maritally.
He's turned into a grade A cunt, an ungrateful bastard who has got too big for his boots by the sounds of it, seen it so many times, so you must stop laying down and hoping that love will save the day.
He can't be trusted and you have a job to do lady, to look after your children and their future, would you want another woman getting your kid's money, no thought not so big girls pants on and stop relying on him being the fair, reliable and honerable person he used to be.
You deserve more than this, you are entitled to far more than he thinks.
Now strong lady get those solicitors numbers looked up and don't believe a word that comes out of his mouth, his actions have shown you enough.