To those saying that the MC is being dense, I'll offer you another perspective.
With how I read it, it wouldn't be hard to suspect her intent, even without being shown directly, like it was to the readers. However, the MC is merely not making assumptions since he wouldn't know for sure unless it was confirmed somehow. The MC was aware of the potential meaning behind the fried pork, but he didn't assume that everyone else knew, so he shared that little bit of trivia along with establishing that he's in a relationship that he cares about.