What would you do ?!

So me and my partner have been together 4 years. I love him dearly .. but .. I really don't like alcohol, & he does, I don't deny him of this but before I met him he used to drink 24 cans a night ! He has cut well back to 4 on a weekend. But recently I've noticed the beer becoming alot more regular & in the week again too. I don't want to feel like a nag but the repetitiveness really does my head in. He calls me when I finish work (6.00pm) straightaway I knew he had had a drink, I come home & ask him how many you had tonight, he says non, he starts repeating himself, so I ask again, his reply was the same. Promising he hadn't. Obviously women always find out, like I did, & he had 1 at my sisters after work. This has really infuriated me & to me is a down right lie ! I hate liars & in the past caught him out on a few with different things. What the hell do I do I'm so angry & most of all so disappointed. He loves me I know that but how can I make him realise I mean business now & literally not taking no more shitty silly lies !