lainiej, personally i wouldnt mind going to something like that on my own, in fact, i'd quite enjoy the "me" time but i can understand why you wouldnt want to go alone! Most people wouldnt.
Why on earth did he only think to get just the one ticket??? Cant he get another one for you?
All you can do if you really dont want to go alone and you cant get hold of another ticket is to sell it but he might be hurt by that. Still, he should know you better than to think its something you would enjoy doing on your own. :-)