Based on the average lifespan of a human of 80 years, with three meals a day, he could still prepare 67,890 meals for Gu Mengmeng. Excluding the meals that they might eat on dates, at work, in the school cafeteria and the times when Gu Mengmeng was craving junk food, he could make about 40,000 meals for her.
If he wanted to make all the dishes that he had learned at least once, he had to prepare three dishes and a soup each meal that they have at home.