My interpretation: A guy's daydream comes true when he marries Jean, a homecoming queen. He won her by charming her - she used to think of him as her white knight. But not any more. Now, a couple of years later, he is still happy, but the novelty has worn off for her. She is depressed because they don't have enough money (good times start when they have money and end when they don't have money). He is not concerned about money (how much do we need?), and he doesn't understand why she is depressed (what can it mean). He is happy just being with her. But he gets up early and goes out to work to earn money for her, and sings this song (which has a cheerful melody, and the lyrics "cheer up") to try and cheer her up.
My interpretation: A guy's daydream comes true when he marries Jean, a homecoming queen. He won her by charming her - she used to think of him as her white knight. But not any more. Now, a couple of years later, he is still happy, but the novelty has worn off for her. She is depressed because they don't have enough money (good times start when they have money and end when they don't have money). He is not concerned about money (how much do we need?), and he doesn't understand why she is depressed (what can it mean). He is happy just being with her. But he gets up early and goes out to work to earn money for her, and sings this song (which has a cheerful melody, and the lyrics "cheer up") to try and cheer her up.