Alcohol dependence. His drinking habits?

My husband is an civil engineer. From his hostel days he used to drink a lot with his friends. Now, after my marriage it has become a serious issue. Though since one and a month he didnt touch alcohol because he saw that our marriage were suffering a lot because of it. But recently, in this month one day out of nowhere he came home drunk again due to some family problem that he couldnt take it. I reacted a lot. Thought he wouldnt do it again, but then he started to come home like this. Today is the fourth day he did this. I dont understand why he started drinking like this again after being not drinking for nearly 2 months. Only 1 year has passed of our marriage but its now tearing apart because of his drinking. I made him understand so many times, but still he is doing it.. I cant take it anymore doctor, please help me. How can i stop his drinking habits?