Der Mustergatte(1959)

Willy Guggenbrühl is a meticulous bank clerk and an extremely shy person. Over time, this leads to his wife Margit becoming bored with him and eventually filing for divorce. Now the otherwise reserved Willy finally awakens from his lethargy and decides to win Margit back. On the advice of his old childhood friend Roger, he decides to make his wife jealous, which sets off a whole series of turbulent developments...