Every person has her/his own opinion about what drives them through life. Thomas Hardy chooses to describe the idea which might drive a person to seek love.
When a sculptor's idea about perfection is driving him to love women in which this perfection resides temporary his whole life is marked by that. It seemed to me like an egocentric way of seeing the beauty in the women which he loved. It was only through the action of his jade "the well-beloved" which he seeks, that any of his romantic interests gained any beauty, and after he considered that the spirit of his well-beloved had passed from that body to another, he only viewed it like a carcass, not able to generate any feelings of attraction.
His pursuit leads him to hurt the first woman which he asked to marry him(Avice), and after meeting the woman's girl(Avice the second) he realizes that what he thought he was searching(the well-beloved), was something that others might search for to, but not under the same name. As fate will have it, he falls in love with Avice the second(her mother dies before) and want to marry her also, but she is wed to another man. He assumes the role of a protector and continues his life, until, after some 20 years he hears again from Avice and goes to see her. Then he sees her girl, a beautiful woman of 21 which resembles most his youth love. She's also an Avice,the third, and he tries to marry her also, but being sixty years old doesn't manage to do that, in spite of the support Avice, the mother, has shown. This intricate plot resumes itself by the death of Avice(the second) after she finds out that her daughter elopes to wed secretly with her sweetheart.
One to many tries for the character, and he falls ill, an illness which has the effect of aging him severely and depleting him of his muse/curse(the search of a well-beloved).
It shows once more that an ideal of something cannot be retain permanently into someone's mind, as the mind is set to age; and that being to trapped in the pursuit of perfection can make somebody alienate from society.
Ultimately he never got a chance to love for a longer time the person in which he thought his Well-Beloved resided. His curse was broken by old age, when he didn't feel any feeling of art, beauty and physical attraction to anybody.