noun
double life
Living two separate lives, often with one hidden from others; can be literal (e.g., secret identity) or figurative (e.g., balancing work and a secret hobby).
彼は昼は会社員、夜はミュージシャンという二重生活を送っている。
He leads a double life as an office worker by day and a musician by night.
スパイは
Spies are often forced to live a double life for many years.