What is the theme of marriage in Jude the Obscure by Thomas Hardy?

Marriage is the central issue in this novel. This is true in the practical aspects of marriage as well as the ideological elements of the institution. 

Jude's marriage to Sue is the most significant one in the novel, but far from the only one. Jude also marries Arabella and Sue also marries Phillotson. Arabella also has a second marriage. 

Each of these unions is examined in terms of its honesty and in terms of its balance. Conversations abound regarding the logic of a permanent bond formed between two humans fated to change their minds about their preferences. 

Jude's marriage to Arabella, like Sue's marriage to Phillotson, grows out of obligation and deceit, not love. Yet the legal bond endures long after the emotional bond is broken. This lamentable fact also is discussed at length. 

The bitterness of "false" marriage marks both Sue and Jude. 

Sue’s marriage to Phillotson has led her to despise the institution, much as Jude’s problems with Arabella Donn had caused him to be fearful.

The practical and legal difficulties that grew from their failed marriages are clearly drawn in the novel. The ideological difficulties of marriage are explored throughout the novel but find fullest expression in the extended pseudo-betrothal between Jude and Sue. 

As Jude and Sue are freed to marry one another after each getting divorced from their first marriages, they postpone doing so.

Several debates take place that articulate varying challenges to the legal structure of marriage, the moral (and demoralizing) effects of marriage on individuals, and the natural resistance of free spirited people to such a permanent institution.

Marriage is defined by rules. Society sees marriage, in this novel, as a set thing. To play with the rules of marriage is to endanger the society. This notion is demonstrated when Phillotson is fired from his teaching position after the town discovers that he permitted Sue to leave him so that she could live with her lover.

Phillotson gives his consent to her departure; when his superiors at the school discover the arrangement, he is relieved of his position.

The town, as a representative of society, was not even slightly interested in allowing a breech of the well-understood protocol surrounding marriage. To challenge the institution of marriage is to challenge the moral authority of society at large. Acting unconventionally leads to ostracism, as we see with Phillotson and later with Jude and Sue as they are run out of town. 

Marriage, in light of these arguments, can be seen to symbolize social rules generally, which often stand in opposition to the will of the individual. 

What is the portrayal of marriage in "Jude the Obscure" by Thomas Hardy?

It is important to also understand the emotional dynamic and gender double standards of behavior for women and for men in the novel Thomas Hardy wrote before 'Jude The Obscure.' This is because the author had already begun to tackle the idea of the honest examination of relationships in his earlier novel 'Tess Of The D'Urbevilles.' In 'Jude The Obscure' he expands the horizons of his theme to include marriage itself. In 'Tess of the D'Urbevilles,' many guardians of the church and of the establishment were outraged at Hardy's contention that despite being violated Tess remained morally pure as a female - what had happened was not her fault, but a man's - and society's. In 'Jude' he painted a satirical picture of hypocritical marriages of the time and in so doing criticized the establishment, the church and the unfair class system. Those critzed saw no evidence of any caring, generous christian God in these novels, only bleak cynicism and pessimism. This may have ben something to do with Hardy's own personality - his dear friend had taken his own life and Hardy had been in love many times, and married more than once. Perhaps he saw no comfort or consolation in his own faith at these times - and saw no loving God sustaining healthy marriages.