Yes, I think that's too many as well. Does he have any hobbies or interests? When you do approach him, I would go under the guise of, "I don't want to upset you, but I am worried for you about how much you're drinking...' and see how he responds? Tricky one. How old is he?
Not an easy one at all to tackle because he is likely to be in denial over the extent of the problem and underplays how much he is drinking.
You do need to talk to him but he will perhaps accuse you of nagging him, says that he drinks to relax or accuses you of being paranoid. You won't get anywhere with him if this is the case. You also cannot make him seek help either if this is not what he wants. He has to seek help for his own self and tackle exactly why he is drinking to excess. He is not your responsibility ultimately.
My counsel for what its worth is to seek support for your own self - Al-anon are helpful to talk to and can help family members of problem drinkers. How many people in real life know about this?. Not many I bet, it also thrives on secrecy and shame. You cannot save someone who ultimately chooses drink over you - there is now another in this relationship and that is alcohol.
What's your role here too - many women become enablers in such circumstances. A role that ultimately helps no-one.
Do you have children?. They need to be considered as well, you are ultimately only responsible for your own self and any children you have.
Children are very perceptive and will pick up on any vibes between the two of you, they will likely see you're unhappy and thus ask questions. Growing up as well in a house with a parent with a drink problem can also cause them emotional harm, problems that may only arise when they are themselves adult.