I think he yearns for love. He paid a lot before, but he never paid it back. You are the best, let her learn a lot from you. What makes him happy now is that he loves you very much and will feel that he is the happiest person in the world.
If someone says to himself, if he really loves you, he should cherish it, work hard together and make progress together. This sentence sounds beautiful, making each other better selves.