Mabel's Neglect
Mabel's doubt of her husband's love of her has been going on prior to the film, it's why it only takes a single day to make her cry. So even in the first strike (where she smiles and shrugs it off), the doubt and worry is still there. It's been months and the neglect has been increasing. In earlier versions of the film I showed scenes through time, like Mabel eating dinner alone, going to bed alone, etc. while Jonathon worked.
However, Mabel sees it as her fault somehow. She's introverted so she would be less likely to blame outside forces like the invention itself. She doesn't feel much anger or spite to the car in this film, as hopefully you can tell, but rather every reaction she has to it is depression-based (depression being anger turned inward, after all!)
Jonathon Lawson's neglectfulness
Jonathon was raised in a much richer family than Mabel though you would rarely guess it by his personality. Since he was a child he was always different and lived in his own little world. He's a thinker and a dreamer, an obsessive person who can easily forget and the people around him. He's not purposely mean to Mabel, he's just distracted and blinded by his vision.
Economic Status
In their original story, I had always thought of Mabel and Jonathon as a well-to-do couple, but their funds are dwindling thanks to Jonathon's eccentric ideas. Jonathon has been long since tied off from his family's wealth for his excessive spending and his, well, flightiness. Not that he seems to notice or mind. It's worth wondering if he's even paid attention his checkbook in the last few months.
Mabel is of a middle class family who wanted their daughters to marry up (since it's so important to women to marry a man with "good prospects", after all). It was just lucky for Mabel that she did happen to find and fall in love with the charismatic, creative, different Jonathon Lawson, which is why she's definitely not trapped necessarily by the idea of having to be in marriage, but trapped by the idea of possibly not being loved in return.
So, in short: she was middle class who married up, so she's by no mean super aristocratic, but she tries her best to be feminine and proper best she can.
