Should I be worried

I just started dating a guy and it's been great. Although he drinks, a lot. Almost every date he stops at the bar or has two drinks at dinner. The other day at the zoo, I noticed he put vodka in his sprite and hid it from me bc he knew I'd be mad. This is not the first time he's "surprised" me with drinks or hid it from me I'm sure. Should I do something or be worried? I am happy but this is concerning me.