His love affair with classical music started at a high school concert.

love 的意思是"爱、热爱"，affair 的意思是"事务、事件"。 love affair 字面意思是"恋爱关系"，在这里比喻为"对某事物的强烈热爱或迷恋"，指对古典音乐的痴迷。