Drained, lets start with what is easiest to change. You say your depressed and have no social life as your taking care of the kids. Ok, Im a mom of three, once again single (was I ever really not?) so I can relate to that but can you start a social life includng the kids, like with PTA, or sports games or school volunteering.. and then as another mom and kids to go for dougnuts or hot cocoa after. Get busy doing, even if its with the kids. Around SAturday zoo trips or whatever with other moms... ect. Join a arts and crafts class with the kids. At first you have to force yourself but it gets easier.
I know your in counseling but I missed if you regularly attend alanon, that too would be a big help.
I know what your going through with the husband. Ive been back and forth so long now, nothing about an addict relationship or use surprises me anymore...nothing.
When the pain of staying is truly worse than the pain of leaving you'll know...and mine threatened all kinds of take away the kids tactics. In the end he's away and Im here with the kids, $ a wreck but we are surviving and Im sleeping well and no more stomach aches.