Deal breaker in relationship

I love my bf of 3 years. He's a great person, and when things are good they are great. We both get along great with each other's family. There is one small problem that really bothers me, which is his drinking. At first it seemed like he was drinking socially, but now I realize it's his favorite hobby, and more like a necessity. Not to mention, when he drinks he goes hard, not just a few beers. I've seen him progress over the years, and have expressed my concern to him that it's a problem. He doesn't think it is since all of his buddies do the same, some worse. He was also raised by a father who drinks daily. Even after 1 DUI (before I met him) he hasn't gotten his act together. I don't want to break up with him over this, but I'm very concerned that it is a problem. I'd hate to start a family and have this problem following us down the road. What do I do?