Sweet wine is loaded with fructose.
I've found the same thing ( not with wine, but in general ), if I find myself making an allowance once, it means going back through cravings. And if I get cravings, I go back and work out how sugar has crept back in. In this case, it's easy. Wine is fruit juice. dry wine is low in fructose, I *think*, but sweet wine is sweet because it's full of it.