By the way, I'd like to correct one thing... the part about diabetes galloping through my family was not in fact facetious. That part is true. I just hope I don't get it. Unfortunately I really like chocolate, and I have been gaining weight lately... fortunately the chocolate I like is very dark chocolate, like 85% cocoa, so that's not TOO bad I guess.
It's sort of easy to avoid diabetes, type 2 that is. However, it's possible that your pancreas can just up and stop working whenever it pleases. The amount of sweets you eat won't lead to diabetes. Not directly. Sugar only leads to diabetes when someone gains weight, becomes insulin resistant, the A1C is elevated, etc.
I'll be your temporary physician. Lose weight, cut carbs, eat more green veggies, and exercise. Blah, blah, blah. Your chocolate intake is most likely fine.