What does the cryptic crossword clue "Unimportant, short-lived ménage à trois? (8)" mean?

The definition is "Unimportant". The wordplay uses a cryptic definition. Cryptic definition The answer is TRIFLING.

Unimportant, short-lived ménage à trois? (8)

Times Cryptic #28997 | 23 Across | 2024-08-16 flower