The marriage was, by Lamarr’s later accounts, controlling to the point of imprisonment. Mandl reportedly tried to purchase every existing print of Ecstasy, believing the film dishonored him. He did not want his wife to work. He watched her with a vigilance she described as suffocating. He converted her to Christianity — formally, for the wedding — though the conversion does not appear to have been accompanied by any sincere change in belief on either side.
What the marriage also provided, involuntarily, was an education. Mandl entertained lavishly. The dinner table at the Mandl household, and at his castle in Schwarzenau, was set for scientists, engineers, military officers, and government officials. The conversations, as Lamarr later described them, ranged across armaments technology: how artillery worked, how torpedoes were guided, how radio jamming could disrupt communications. She was young and she was expected, in the social conventions of the time, to be decorative rather than participatory. But she listened.
Whether those conversations gave her specific technical knowledge that she later applied to the patent, or whether they gave her a framework of awareness that made her receptive to George Antheil’s ideas, is a question the historical record does not cleanly answer. The ETHW (Engineering and Technology History Wiki) notes that Mandl “introduced her to the underlying idea” — but this is, necessarily, a reconstruction based on accounts that were recorded years later, primarily by Lamarr herself. She had every reason to emphasize this element of her background, and the dinner-party anecdotes are vivid, perhaps too vivid to take entirely at face value.