Emma's lowlier status is beautifully summed up in the line "see the white dress of her first communion lengthened for the occasion ".
of course adultery was frowned upon in the 1800's. in particular when the adulterer was a woman. how much if any do you think emma's "humble" beginnings play into her choice of lovers?
Since Emma was without an abundance of choices because of her father's modest income and thus married to a man who was uninteresting and passionless and whose conversation was "flat as the sidewalk of the street," it makes sense that she would be easily beguiled and seduced by male potency in various personages, like the unscrupulous Boulanger and the romantic dreamer Léon.
I think that this class argument can be used fruitfully to comment upon the choice of lovers that Emma takes later on in life. In a sense, we all are aspirational individuals in the way that we want a better life for ourselves, and often this can be reflected in the kind of partners that we try to look for or eventually find ourselves with. This, to my mind, is a perfectly legitimate approach to take in studying this novel. It is certainly true in her relationship with Monsieur Rodolphe Boulanger, for example.