Introduce yourself and your spouse on the first night so the waiter and bar server will know you are a couple. When ordering beverages, have your Sign & Sail card ready when he takes the order so he will jot down your Cabin Number. Place the order just for you and your spouse. They are pretty used to groups. Should you wish to buy a bottle of wine and share with the table, if accepted, it is common courtisy for someone else to reciprocate and buy the next night. Of course this doesn't always happen. If you wish to purchase a bottle of wine just for yourselves, you can ask to have it "capped" an served again the next night. We do this often with a Red & a White as we have different tastes.