In almost all of his novels, Hardy explores and questions the institution of marriage. We see it from the very beginning of The Mayor of Casterbridge, when Henchard complains about being unhappy in his marriage. Since divorce wasn't an option in those days, he actually auctions his wife off to the highest bidder. After that first scene, the novel explores the question of what a husband owes a wife, what a wife owes a husband, and how "marriage" can be defined.
In The Mayor of Casterbridge, "marriage" seems to be less of a traditional, legal contract than an agreement between two people. Susan's relationship to Newson and Lucetta's understanding with Henchard are just as morally binding as a traditional, legal marriage.
Henchard's proud independence makes him view marriage as a set of duties imposed upon him by his wife, rather than a reciprocal relationship. Because he does not expect anything in return, he comes to see marriage as a financial and emotional drain.
If there are a lot of marriages without love in The Mayor of Casterbridge, there's also a lot of love without marriage. Lucetta falls in love with Henchard, then their marriage is postponed and then canceled altogether. Elizabeth-Jane crushes on Farfrae from afar for most of the novel. Henchard's loathing for his stepdaughter gradually morphs into a kind of hopeless, protective, and jealous love. She might be the only person Henchard ever really learns to love.
When Elizabeth-Jane first falls in love with Farfrae, it is in part because "he seemed to feel exactly as she felt about life" (8.33). In a sense, therefore, her love for him is really a narcissistic love of herself.
Elizabeth-Jane's affection for Farfrae is so pure that she is not willing to cause either him or Lucetta pain by acknowledging her jealousy and disappointment.
It's hard to say what first attracts Henchard to Farfrae, but whatever it is, he trusts him immediately – not just with his business, but with his personal life and secrets. The two men are practically inseparable…until Henchard's jealousy drives them apart. Elizabeth-Jane and Lucetta are likewise inseparable, despite their contrasting personalities, but Elizabeth-Jane, unlike Henchard, is too good of a person to allow her jealousy of Lucetta and Farfrae to end their friendship.
In the two main friendships of the novel, Henchard feels more attached to Farfrae, and Elizabeth-Jane feels more affection for Lucetta. It seems impossible in the world of the novel for the affection in friendships to be balanced and reciprocal.
Henchard's capacity for both love and hate is stronger than Farfrae's.
For such a long novel, The Mayor of Casterbridge has relatively few main characters: two men (Henchard and Farfrae) and three women (Susan, Lucetta, and Elizabeth-Jane). Their great differences of character make it difficult to generalize about gender roles in the novel. The characters themselves, though, often make sexist generalizations.
The Mayor of Casterbridge presents several contrasting versions of masculinity and femininity to show how difficult it is to define or maintain hard-and-fast gender roles.
Although Elizabeth-Jane is naturally very feminine, she lacks the more superficial, artificial markers of femininity that are taught by society, such as feminine handwriting, fashionable dress, and accomplishments like dancing and singing.
The events of The Mayor of Casterbridge span more than twenty years – most of Henchard's adult life. In a sense, you can read Henchard's downfall as a commentary on the way the past always comes back to haunt you. There's no way to outrun your past actions. Lucetta's death is likewise caused by past events coming to light. In the world of the novel, history always repeats itself, and your past actions will always come back to bite you.
In The Mayor of Casterbridge, the past continually comes back to haunt the present.
The Casterbridge Ring represents the tendency for history – even ancient history – to repeat itself.
Casterbridge is about as "natural" of a town as you can imagine. It's set in the middle of agricultural fields and doesn't have a lot of the "unnatural" industrial mills and factories that were springing up at the time in towns further north in England. The town's naturalness contrasts sharply with the artifice (fakeness and superficiality) of some of its inhabitants. Lucetta, for example, is always thinking about what she wears and how she carries herself. Elizabeth-Jane, on the other hand, is completely natural – she doesn't think about these things at all.
Casterbridge, where most of the novel takes place, represents a kind of compromise between city and country life, and between civilization and nature.
Elizabeth-Jane's natural intelligence and morality form a sharp contrast to Lucetta's artificial, assumed accomplishments and her socially imposed value system.
It's clear that almost all of Henchard's misfortunes are caused by his own mistakes; it's hard to blame "fate" or "destiny" for the bad things that happen to him. But at the same time, how much control does he have over his mistakes? In the world of The Mayor of Casterbridge, it seems that characters have very little control over their own personalities. Henchard is born with a bad temper and very little self-control. If he becomes jealous or angry, he'll act on his jealous rage. If his mistakes are a result of his personality flaws, which he was born with and cannot control, how much "free will" can we say that Henchard really has?
Henchard never blames outside forces for what happens to him, because the forces that bring about his downfall are all internal.
Although readers might feel pity for Henchard's misfortunes, they are all caused, either directly or indirectly, by his own actions.
There are a lot of broken dreams in The Mayor of Casterbridge. Elizabeth-Jane is hopelessly in love with Farfrae for most of the novel and is forced to watch him marry her best friend. Henchard has big plans and watches them fall apart because of his own mistakes. Farfrae is the only character whose cheerful nature seems to leave him immune to the pervading dissatisfaction in this novel, and even he has to deal with some disappointments.
In the world of The Mayor of Casterbridge, it's impossible to live down the mistakes made in one's youth. Any attempt to escape past errors leads to broken dreams and dissatisfaction with life.
Henchard and Lucetta both have unrealistic dreams and ambitions and very little control over their passions. It is not surprising, then, that they are the two characters most susceptible to bitter disappointment.