梦里梦外都是他梦里梦外都是她
[mèng lĭ mèng wài dōu shì tā mèng lĭ mèng wài dōu shì tā]
It poetically depicts obsession by indicating thoughts revolving around a specific 'he' or 'she' continuously, whether dreaming or waking life. There’s an implication of undying infatuation or profound emotional attachment to someone special.