Helping a alcoholic that is functional

I am so hoping that someone/anyone can give me advise to help in a functional alcoholic. My boyfriend and I have been together for 6 yrs and just started living together within the past year. I didnt know he was an alcoholic till I moved in, I just thought he was a social drinker.

Now I feel completely lost and confused on how to help him and how I didn't know before this. But I know that functioning alcoholics make it appear as they are normal and it is just social. He goes to work every day and on time, he has his own home he has a mortgage for, he raised his son just fine. I just never seen it till I moved in.

I love him with all my heart, but the liquor is becoming a problem. I dont know how to help him. I dont know how to talk to him differently about it ( because ive tried talking to him about it and he denies it bc he is functional). He drinks excessively every single night from the time he gets home from work till he goes to bed, and his mood has gotten worse and his comminication skills have been siverly lacking. I know his problem is getting worse bc it is becoming more noticeable.

Please any suggestions or tips would ne greatly appreciated