Personal life and death
In 1934, Stradner married German stage and film director Karlheinz Martin, who was 27 years her senior. When MGM placed her on contract, Stradner's marriage and past film career was expunged from the public. She later returned to Europe and divorced Martin.
At MGM, Stradner met Joseph L. Mankiewicz, who was instructed to help improve her English as he had with other German-speaking actresses. The two were married on July 28, 1939, at Mankiewicz's sister's apartment in New York. When they returned to Los Angeles, on Stradner's 26th birthday, MGM studio writers and producers greeted them at the railway station with rice and a ten-piece orchestra. Stradner gave birth to two sons, Christopher, born in 1940, and Tom Mankiewicz, born in 1942. In November 1944, the Los Angeles Times reported that she and her husband had mutually agreed to separate, though it was short-lived.
Stradner, at the age of 40, underwent a hysterectomy while her husband was filming The Barefoot Contessa (1954) in Rome. Her emotional breakdowns has been speculated due to her own fear of aging and losing her sexual attractiveness, which was made worse by her husband's extramarital affairs. Fred Hacker, a psychiatrist Stradner had known since her stay at Menninger's, stated: "Joe was advised many times to separate or get a divorce. He always promised that he would at some future date, that he would only remain until a particular crisis was over. So it was always clear the attraction she held for him, although I'm sure that he was not entirely faithful during those periods."
Throughout their marriage, Stradner was often hospitalized for extended periods. Long suspicious of her husband's serial philandering, Stradner confronted Joseph with an allegation he was having an extramarital affair with Rosemary Matthews, a production staff member, while he was filming The Quiet American (1958) in Saigon. Stradner suffered a mental breakdown, in which Joseph contacted his sister Erna to accompany Stradner and have her hospitalized in a Viennese clinic. There, Stradner was treated by Fred Hacker. In July 1957, she flew back in the United States to finish her recuperation in a Connecticut clinic as advised by Lawrence Kubie. Stradner suffered another manic episode, and Kubie sent her to the Neurological Institute of New York.
On the night of September 26, 1958, at their summer home in Mount Kisco, New York, she and Joseph fought, and he left for New York City to work on his Broadway play. Hours later, he contacted his niece Josie after Stradner had not been answering the phone. On September 27, Stradner was found dead lying on the floor near a writing desk, at the age of 45. She was found holding a "nearly indecipherable note" in her hand, stating she was "tired". Her death was ruled a suicide through an overdose of sedatives. She was interred at the Kensico Cemetery in Valhalla.
