I went to an all-inclusive last summer (buying an all-inclusive was cheaper than not, so that's the route I chose and don't regret it) on the Mexican Rivera and had some amazing non-alcoholic drinks. I kept busy with activities during the day (horseback riding, snorkelling, working out, massages). I wasn't tempted at all. I had coffee and fresh juice delivered to my room and enjoyed the tropical setting each morning. I was by myself and looked at it as a personal retreat. I just didn't consider drinking as an option. I quite enjoyed myself.
HOWEVER, you know yourself and if you feel like you won't be ready by then and can change your plans, then I'd do it. I had far more sober time than you will have by December, so there's that too. I'm glad you have the support of your boyfriend no matter what you decide.
Just thought I'd pop in and say it can be done and be enjoyable but you have to make sure that drinking just isn't a part of your life anymore in order to not be resentful or struggle (or relapse!) on your much needed holiday.
Good luck and stay sober--it's worth it, hon!