i wholeheartedly believe that 40-50% of women pre feminism weren’t loyal either despite the stigma. I mean think about it. The average men during the industrial revolution was working 10-12 hour shifts. Taking care of a small house and cooking a meal would take like 4 hours realistically. What was the woman doing for the other 6-8 hours? staring at a wall? Their boredom definitely caused a fair amount of women to cheat during that time. I remember seeing somewhere that during that time 50% of men also had cheated with prostitutes. Most people in general were cheating during that era.
Which is true, the red light was not the same as it is today, it was very much open.
In the 40's men who didn't visit brothels weren't considered 'men', this is true for Brazil at least, more 'Christian' countries were safe-ish from that 'rule'.
As for women I believe the same, I mean today we have what we call 'backup guy', the woman goes to work, a man hits on her there, he gets her number and goes home, if the relationship is not going 'well' she has a guy on demand.
It was the same back then, but things were more 'physical'.
And in WW2 was very, very common for 4-F men to hit on women, think about this, almost 40% of a town serving, you are a natural pussy hound, what would YOU do? hit on every single married woman of course.
Cheating was and will be always be a thing, 'love' was extremely rare as well, as people just dated the first one that hit on then back in the day because they didn't want to miss any opportunities, today women don't fear that as much because how many men are willing to wait for then even in their mid 30's.
Back then a 20 something alone would be VERY scared of dying single, today they don't have that fear.