The Persistence of Desire, by JOHN UPDIKE.

Page 568.

“I am, I am; but” the rest was so purely inspired its utterances only grazed his lips-“happiness isn’t everything.”
He is happy, he is successful, but Janet represents his youth, and carefree life that he can no longer have. She is a love a long time forgone and yet, she represents more to him then loves. She is his childhood, his adventure, his old town; she is simply a nostalgia that he longs to bring back.

Page 569.

“The neutral ominous, ‘he’ opened wide a conspiracy Clyde instantly entered. He stayed behind a minute, to give her time to get away. Ringed by the judging eyes of the young and old, he felt like an actor snug behind the blinding protection of the footlights;”

He realizes that the love between him and Janet is a time gone by. He is no longer the man in her life, and he must let go of their love. As all the other people in the waiting room are judging him, he realizes he is a smaller player in her life. He is in the background of her past.