Also, Tess is passionate in her love for Angel and her hatred of Alec. She strays from her marriage only when it appears that Angel may not return to her from South America and when there is no other way to help her destitute family. When she discovers Alec's duplicity, she makes her mind up that this will be his final deception of her.
The martyr-like passion of Tess engenders the readers' sympathy. She makes several attempts to rectify her "mistakes": the vow to Angel to end their marriage; her offer to kill herself to free Angel from their marriage; and, her refusal to ask Angel's parents for any additional money during Angel's sojourn to Brazil. She is determined to be self-sufficient and willing to sacrifice her well being for the good of others. This makes her selfless and on a morally higher ground than other characters in the novel.
Tess' greatest weakness is for her family, particularly her brothers and sisters, and it is this weakness that Alec exploits to great effect. Her journey to The Slopes, at the beginning of the novel, and her subsequent return to Alec near the novel's end, are all predicated on her willingness to undergo great pains to make her family's life better. Alec promises financial aid to the Durbeyfield family several times, to which Tess cannot object. He has ulterior motives, however: to subdue Tess and make her his own. In the end, Alec fails. Thus, Hardy paints a grand portrait of a well-rounded character in Teresa Durbeyfield.
