I would have to ask how you portrayed the husband. Was he reluctant because he'd be accused of being a pervert? Was he gathering evidence to confront and divorce the wife later? Or was he pulling his pud, or coming in his pants as he watched and too conflicted to say anything later? The reaction would differ wildly as would the scoring.
The husband in this story was in a dilemma - he suspected his wife was being disloyal but once it was confirmed - he didn't know what to do. Plus they were hundreds of miles out at sea three days from New York and the husband didn't want this to become public knowledge in high society, especially in those long-gone days. Complicating things is that he next saw his wife's younger sister getting changed, then the pretty maid who secretly tries on one of the wife's dresses, and enjoyed seeing these things. The husband did get an erection watching his wife and her lover having sex but he was dismayed by this reaction, eventually chalking it up to an experience like laughing at a funeral.