I'm sorry you are going through this and I'm very sorry for the loss of your baby girl.
My husband is an addict and it's rough. Separate your finances right now as best you can and hide any money, credit and debit cards and checks. If you have jewelry you value, hide that. I'm not kidding. My husband pawned my wedding ring once to buy drugs.
Sadly, you can't make him stop but you can protect yourself and your boys. Check out the forum on here for family and friends of substance abusers. There are a bunch of really great, supportive people there.
Hang in there!