I am incline to agree he has issues with drugs, though most drug dealers do not do drugs because they are there to make money.
You live your life that's how you treat an addict who is your husband. You go on each and everyday with your child the best way you know how. Right now he has his support his family which is good for him. Who do you have? Do you have friends and family who will support you emotionally if you need them? Because you are most definitely going to need them.
At the end of the day what do you think regarding your decision to leave him? I think you did great personally.