I am with Barb. Do not wait any longer.
Simply call him back, and ask him to meet you in a coffee shop or something. Be gentle, be direct, but be firm.
"X, I am no longer willing to pursue this relationship with you. We have had some wonderful times, but I need to step back and re-assess my life and what I am doing. I am wishing you the best in your future. Please do not call me any longer. I have chosen to move forward on my own. Take Care."
And that's it. You do not need to explain what, where, why. You have simply decided to move on. And for me, I wouldn't mention the alcohol. He knows the REAL reason, and re-affirming it, only makes him defensive.
After you have said that, get up and leave. No more conversation, no drama. You have every right to control who you see, and when.
PS, I would also change my phone number before this goes down. NC means..NC.
Prayers going to you! I am proud of you for taking this step. But do NOT wait another day!