I think in your boyfriend's situation, it's all or none. He can't be a social drinker. So unless he's willing to go totally free from alcohol, you're in for a really rough ride married to him. From what you have posted he is going to try to moderate his usage and that's not going to work. For a social drinker there is no moderating drinking--it just happens naturally. At least it does for me. After I first start to feel relaxed, that's it for me. No more alcohol. I don't want anymore. Can you see your boyfriend being content with only a couple drinks consistently? I don't.
Take this opportunity to learn from other people's experiences who have traveled the road you are contemplating traveling. You are being given the gift of choosing which path you are going to travel. Choose the path wisely.