What matters is obviously per person... So "if you are a couple" is completely irrelevant.

Terms like 'light', 'moderate' or 'heavy' drinking are relative and must be taken in context.

For instance, historically it has been customary in many countries to drink wine with every meal. So 2 bottles per week is indeed moderate as it's about 1-2 glasses per meal. Likewise, 3.5l a beer per week is one beer at dinner, which is considered quite moderate, indeed.

Basically, if your drinking is moderate during meals only and no hard liquor this is considerate 'moderate' to normal in traditional terms.

For the context, I am French, living in Germany. As a tradition (but maybe I am old) you never drink wine alone. This is why my remark "as couple" because it is the minimal number of people you need to drink. But again, this is my education, so very personal.

3.5liter beer per week is just one beer per day which a lot of people consider completely benign.