短语 “my one and only” 用来形容 “某人生命中最重要的那个人”，即 “我的唯一”。它用来表示 “此人是我唯一心爱的另一半”。短语中的 “my（我的）” 可以用其它形容词性物主代词替换。

• My partner is amazing! I love her so much. She is my one and only.
  我爱人真是太棒了！我非常爱她。她是我的唯一。
• I proposed to my girlfriend because I knew I wanted to spend the rest of my life with her. She is my one and only.
  我向女友求婚是因为我知道自己想和她共度余生。她是我唯一心爱的人。
• That's so cute that you told him he was your one and only. You two make an amazing couple.
  你告诉他说他是你生命中的唯一，真是太好了！你们俩是天生一对。