To some degree having to have booze at your party is alcoholic thinking. I know when I drank I thought everyone in the world drank maybe not to excess but drank and wanted to drink. After being sober for a while I have found there are a ton of people who do not drink and a ton who just do not care if they drink or not.
Someone mentioned the very real liability factor of serving alcohol at a company event. I'm sure it would **** off the alcoholics but about 80-90% of your employees will not care. Blame it all on the insurance company's and lawyers (sorry insurance people and lawyers) but have a dry party.
Realistically you just have to stay sober today and remember FEAR stands for Future Events Appear Real. Stay out of the future and the past so you can live today