I was an alcoholic for the better part of 10 years. I'm 36. I ended up in hospital last year from having considerably too much "fun" with alcohol for that long, I assure you it was no fun at all. I've been sober for 6 months now, and I don't intend to go back to drinking.
The most important thing for me in finding "fun" again and filling that void, was to come to terms with why I drank, and that was to be a "different person", for me anyways.
Except I am that person, I just found it difficult to live, and alcohol helped ease that, made me feel confident, etc. Now that I don't drink I see it for what it is. I can indeed be that person without booze, I just need to learn more about... I guess who I am, and how to "channel" that person, the first step in that was stopping drinking, you literally cannot do that self discover otherwise. On the other fronts, after I stopped I continued to go out and hang out with drunk people (not popular advice, however it was important to me to prove to myself I had that control) - discovered 2 things: drunk people are pretty annoying, it's kinda in a way more fun watching everyone else when they're drunk. I don't really talk about it when I go out, I just go out, order diet cokes, and no one really notices or cares. However, going out in that setting is pretty infrequent now, once a month at best. The rest of the time I've spent working on me, reading a lot, learning new things, it's easy to burn 3 hours on the DW docs youtube. I also work on my relationships with others now, and I find more time to volunteer and do things for my community, it's a lot of fun! I feel an urge to drink near every single day, sometimes multiple times a day, if I walk by a wine store the feeling I get is hard to describe, spending time thinking about what the reward you're going to get, and then applying that to something else, helped me immensely find new fun things to do.
Do I miss going out and getting drunk with my friends who regularly go out and get drunk: sometimes.
Has it been difficult finding new friends, especially later in life: yes.
Do I have fun and enjoy life more without alcohol: absolutely.
This doc is really really really good: https://www.youtube.com/watch?v=RX2opvj7WE8