Angel causes Tess more suffering because she loves and believes in him, only to be cruelly rejected. Alec, although he "ruins" her by "seducing" (raping) and impregnating her when she is very young, is not a person who touches her deeply enough to hurt her the way Angel does. Alec violates her body, but Angel violates her soul.

Tess trusts Angel. When they marry and he feels he has to confess to former infidelities, Tess believes she can confess in turn what happened with Alec. It doesn't occur to her that Angel is a shallow, hypocritical Victorian male who has internalized the double standard. While, in his mind, it is permissible for him to come to the marriage not a virgin, because he is a man, he doesn't allow that of Tess, a woman. His rejection of her for her "impure" past is painful to her because she had invested so much into him emotionally and had expected more of him.

When Tess, devastated to the core, returns to Alec after Angel's rejection, she becomes his mistress. Alec tells her they are the same: they are both people who pay for their crimes to what he calls the uttermost farthing. In some ways this is true: Tess murders Alec and then awaits her own death, while Angel gets away relatively unscathed for the pain he has inflicted.

Well, on the one hand automatically the way in which Alec is the author of Tess's downfall through seducing her and his presentation as a n'er-do-well should make us question this statement immediately. The way in which Alec is presented as a devil-like figure is clear from the conversation he has with Tess when he is holding a pitchfork towards the beginning of the novel, and his seduction of Tess is explicitly linked to the seduction of Eve by the Serpent in the Garden of Eden. It is his seduction of Tess that ruins any chance for happiness that she might gain in life, and it is this seduction to that is the means for Angel Clare abandoning her.

However, at the same time, perhaps we could argue that Angel Clare makes Tess suffer more precisely because of his goodness and the way in which he leads Tess to believe he is the opposite of Alec. This makes her depression and her feelings of pain all the more acute when he leaves her after discovering the truth about her and Alec. We expect Alec to be bad because of the way Hardy presents him as a demon-like figure, however, we do not expect the angel-like Angel Clare to be so demonic in the way that he shuns Tess and abandons her. This would suggest that Angel Clare hurts Tess more than Alec overall.