You do really need to speak to your husband calmly about his addiction and how it is affecting you and your children.
Let him know what you have told us on here about how you feel and how you have felt like leaving out of desperation. Be honest with him and yourself. Can it get any worse if you do?
Hopefully he will realise what he is putting you through and will seek help for his addiction. But like Danman says you have to want it and cut all ties with your cocaine triggers being it friends, family and alcohol.
I wish you all well.