Escapade (1980)

Edith and Wolfgang have been leading a harmonious family life in relative prosperity for many years - with a new apartment and a Trabant. They have had a son for five years. Edith has long since gotten over Wolfgang's infidelity twelve years ago, from whom there is a daughter. Every now and then he visits 12-year-old Sandra, merely fulfilling his fatherly duties. But suddenly the girl is at the door. The mother died in an accident. Sandra is accepted into the family and Edith learns that Wolfgang has led a double life over the years and that his relationship with Sandra's mother never ended.