"...In Sternberg's version of the script, Helen (Marlene Dietrich) gives up a glamorous career on the stage in Paris, and also her engagement to a millionaire, Nick (Cary Grant), in order to return to her relatively impoverished husband Ned (Herbert Marshall), and son, Johnny....
"Blonde Venus" is paradigmatic of the complex combination of imposed and self-censorship, that accompanied the Production Code restrictions. In an effort to get the film produced, Sternberg was forced to revise the script three times. As a precautionary measure,the producers at Paramount, revised the original script to submit to the MPPDA.
" Industry censors, however, object(ed) vociferously to the studio's ending. Lamar Trotti (the censor in charge of this project) writes: "It does not seem proper to have (Helen's) affair justified in the minds of the audience by tearing down the character of the husband, who, up to this point, has been a decent man who was deceived by his wife." Trotti complains about the way in which the studio's version undermines Ned, a character who for him, represents a moral position or point of view. This kind of reasoning is quite typical of industry censors, who routinely sought to justify what they deemed offensive material within a script on the basis of a moral that could be attributed to the ending. According to what was known as the rule of "compensating moral values," censors generally advocated the final punishment and suffering of "bad" characters or their regeneration. The problem with the studio's ending of "Blonde Venus", then, for Trotti is that of compensatory logic has gone askew.One act of adultery is balanced, "justified," by something still worse. That is Helen's affair, which is motivated at the beginning of the film in terms of financial need, as a sacrifice to have her ailing husband, is made to look good in relation to Ned's illicit liaison."
Source: Lea Jacobs, "The Censorship of the Blonde Venus...", Cinema Journal 27, No. , Spring 1988, pg. 21-31