My Sister My Love (1966)

Sweden in 1782. A young nobleman, named Jacob (Per Oscarsson) returns from France to his home and cherished sister Charlotte (Bibi Andersson) who is engaged to Baron Alsameden (Jarl Kulle). The siblings close relationship becomes incestuous and with fear that the disclosure of Charlotte's pregnancy will make society view them as libertines, the lovers ultimately choose to part, Jacob decides to leave the country and Charlotte if left to marry the Baron.