Conversation so far:
What year did Hedy Lamarr marry the first time?
On August 10, 1933, at the age of 18, Hedy Lamar married Friedrich Mandl, then 33.
Who did Hedy Lamarr marry?
Hedy Lamar married Friedrich Mandl.
Where did Hedy Larmarr meet Freidrich Mandl?
Admirers sent roses to Hedy Lamarr's dressing room and tried to get backstage to meet her. She sent most of them away, including an obsessed and insistent Friedrich Mandl.
Where were Hedy Lamarr and Freidrich Mandl married?
Their wedding was in the Vienna Karlskirche, also called the The Rektoratskirche St. Karl Borromäus.
What happened during Hedy Lamarr's and Freidrich Mandl's marriage?
In her autobiography Ecstasy and Me, Hedy Lamarr described Friedrich Mandl as an extremely controlling husband.
Why was Freidrich Mandl described as a controlling husband by Hedy Lamarr?
Hedy Lamarr claimed she was kept a virtual prisoner in their castle home, Castle Schwarzenau  in the remote Waldviertel near the Czech border.

Question: What did he do to control her?
Self-contained rewrite: What did Freidrich Mandl do to control Hedy Lamarr?