More unfortunate choice of wedding vows? (6)

I believe the answer is:

poorer

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'more unfortunate' is the definition.
('poor' can be similar in meaning to 'unfortunate')

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for poorer that I've seen before include "More impecunious" , "Less well-off" , "'Having less money, fewer possessions (6)'" , "Less rich" .)

I've seen this clue in The Telegraph.

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