Pasta, olive oil and a bit of cheese is Italy's typical ultra-simple dish for a troubled stomach or a fast meal. 80 minutes should suffice to digest it (and 15 minutes to cook), so it is perfect if you're busy and need a quick meal. With tuna you also have proteins, even. Integralist Warning: Italians would never eat tuna, cheese and olive oil together. There is a good reason: one of the ingredients can easily cover the flavour of the other two. I doubt 99.9% of naysayers understand this: I do, and get the balance right (but you like Pecorino? Colour me impressed!).
I dislike acidic olive oil, but as a rule of thumb "acidic"=southern mediterranean regions (Greece, most of Spain, most of Portugal, Southern Italy, Turkey), "mellow"=central mediterranean regions (Northern Spain & Portugal, Southern France, Central Italy, Balkan countries). Rest is a butter/animal fat netherworld with awful taste in just about everything; "nuke from orbit, it's the only way to be sure", to quote Ripley from Aliens. I probably come from East of your sweet half, so anything acidic feels like an attack to the taste buds.
"Cacio e e Pepe" tells me that your sweet half is probably though not necessarily from Rome or its region, Lazio. If yes, you can ask her about Gricia and Carbonara (and Porchetta, which is a pulled pork sandwich). If she is from Rome, at some point you should visit the capital, watch Alberto Sordi's movies, and try to eat "cucina giudea", i.e. sephardi (Jewish) dishes that have become common staple in the city (e.g. filled artichokes and eggplants). Sergio Leone was a great lover of Roman traditional (and very low class) dishes, his family being originally of humble origins, but his parents becoming well-respected professionals in Cinecitta' (=Rome's studios).
...I am almost tempted to commit another sin and watch the new The Naked Gun movie. The idea of Liam Neeson playing an absolutely serious violent cop in a silly comedy sounds almost appealing. Almost.
"The only desire the Culture could not satisfy from within itself was one common to both the descendants of its original human stock and the machines [...]: the urge not to feel useless."