You don’t marry one person; you marry three: the person you think they are, the person they are, and the person they are going to become as the result of being married to you.

The remark frames marriage as a relationship with a moving target: a spouse is not only a present reality but also an imagined figure shaped by projection and hope, and a future self altered by the marriage itself. It warns against marrying an idealized image (“the person you think they are”) and urges clear-eyed acceptance of the partner as they actually are. The third “person” emphasizes mutual influence: spouses actively participate in each other’s development, for better or worse. The quote’s ethical edge is that commitment entails responsibility for the environment one creates—marriage is not merely finding the right person, but becoming a formative presence in another life.