noun
couple where the wife is larger than the husband
Idiomatic expression literally meaning 'flea couple', referring to a married couple in which the wife is physically bigger than the husband. Often used humorously or affectionately.
あの二人は蚤の夫婦で、奥さんのほうがずっと背が高い。
Those two are a 'flea couple' — the wife is much taller.
うちは蚤の夫婦
We're a flea couple, so we often get teased.