二人は伴侶、三人は仲間割れ（ふたりははんりょ、さんにんはなかまわれ）

Japanese vocabulary

Meaning: two is a company, three is a crowd; one companion is better than two

See it used in real works

• Example sentences from Japanese novels & web fiction (Massif)
• Hear “二人は伴侶、三人は仲間割れ” pronounced in real videos (YouGlish)