Well done happy! Recognising that we have a problem and taking steps to try to nip it in the bud gives back a measure of the control we feared we'd lost.
Let's face it, booze is very more-ish! And it gives a nice buzz. When you've had surgery to limit the amount and type of food you eat, it must create a 'gap' of sorts; at certain times during the day and evening you probably used to snack, and now, you don't. But it had become habit and the body 'wants' something to replace the lost nibbles. One glass of wine so easily becomes three, doesn't it? Goes down a treat, too!
I find evenings hard even now because I have a low boredom threshold. A lot of my old snacking behaviour was habit; when I am bored or restless I want to eat. It's like an automatic response and whilst I know it isn't so-called 'genuine' hunger, it sure feels like the real thing!
So I am guessing that you experience the same habitual desire to treat yourself and, since you are no longer turning to excess food, the wine 'steps forward' to take its place.
By dealing with this so openly (and bravely!) and by making up your mind to avoid booze until your regular Saturday night out you have taken back your control. Well done! Now, as you say, you just need to find something to keep you occupied at certain times every evening!