Do you have joint credit card accounts? If so, you need to either remove his name or set up a new account for you and have your name removed from the joint account. Why? Because if he's in full blown replay, he will charge to the hilt and you, as joint card holder, will be responsible for any debt that he incurs on that card.
As for joint checking and savings, if you start to see spending activity that you cannot account for, move some of the money over to an account for yourself.
Since you are paying the normal bills...you are seeing the activity there.
When separation divorce talks begin and there is financial assets involved, you will need to leave your emotions at the door. Yes, you love him, but you will need to look at the monetary situation as a business deal. You cannot think that he will do right by you. Why? If he full blown mlc, he will lie to you about things, just to get what he wants. You cannot afford to wear your heart on your sleeve when discuss your assets. You have to think and talk like a business partner during the negotiations.
As for the BS he's telling you, is it memorex or is it real? If it's memorex, let it go. They rewrite history to justify what they are doing and have done. Listen, but do not get into an argument or heavy discussion about it.
BTW, you can't fix him, only he can do that. You have to take care of you and your children.