Puer Aeternus

Puer aeternus is Latin for eternal boy, used in mythology to designate a child-god who is forever young; psychologically it is an older man whose emotional life has remained at an adolescent level. The puer typically leads a provisional life, due to the fear of being caught in a situation from which it might not be possible to escape. He covets independence and freedom, chafes at boundaries and limits, and tends to find any restriction intolerable.

Read more about Puer Aeternus:  The puer in Mythology, The puer in Jungian Psychology, Peter Pan Syndrome, Notable Modern-day Peter Pans