It's common to split food with people at your table, but usually this applies to antipasti or second courses, rather than splitting a pasta dish. All this said, the world's your oyster when it comes to eating out in Italy, so get what you want and leave the rest.

In Italy, the etiquette regarding splitting meals depends heavily on the type of establishment and the specific course being shared. Generally, it is perfectly acceptable and quite common to share antipasti (appetizers) or even a contorno (side dish) among a group. However, splitting a primo (first course, typically pasta or risotto) or a secondo (main meat or fish course) is often viewed as slightly unusual, though not strictly forbidden. In more formal restaurants, if you wish to share a dish, it is polite to ask the server "possiamo dividerlo?" (can we divide it?). Often, the kitchen will plate the portions separately for you, sometimes for a small "coperto" or service fee. In casual pizzerias or trattorias, sharing is more relaxed; many people might order several different pizzas to try a bit of each. The key is to ensure that you are still ordering a reasonable amount of food for the table; sitting at a busy restaurant during peak hours and splitting a single bowl of pasta between two adults might be considered rude to the proprietor who relies on table turnover.