My husband is not religious and believes alcohol is allowed in Islam. He wants to drink monthly. I am concerned he may drink secretly despite my objections. How much can I intervene, and is it appropriate to consider leaving him and the kids if he does?
Drinking alcohol is definitely Haraam (Forbidden) in Islam. You try your best to help your husband to avoid such sinful act. If he insists on committing sins, you will not be responsible as far as you don't help or assist him in committing the sin.
Wassalam.