***not an attorney***
It's my understanding that if you sell off MARITAL property while you're still living together, and you use that money for MARITAL purposes (example, fixing a marital vehicle, buying groceries, paying a debt that was acquired during marriage no matter whose name it's in), then that money that is used is NOT subject to distribution.
Now, if you were to take Marital funds and use it for NON-marital purposes (examples, drugs, gambling, stripclubs etc), then that money would be subject to distribution. So, from what I've experienced in my own divorce (and the money that my ex spent during the marriage on non-marital things and that he sold marital property) is that as long as you use the proceeds from selling the marital property on marital purposes, you're in the clear. Your husband my be one pissed off s.o.b, but legally he cannot stop you from doing it.
Regarding the separate account, 1/2 of whatever is in that account will be yours if you separate because it is all marital funds from what you described. So, if you have a way to get the information on that account (account # etc), that will help you in the long run.
I don't know if what he is doing is illegal per se, but it sure is a crappy way for a husband to treat his wife and children. I'd be getting ready to leave if it was me.
Again, not an attorney...