Willoughby -- he whom only half an hour ago she had abhorred as the most worthless of men -- Willoughby, in spite of all his faults, excited a degree of commiseration for the sufferings produced by them, which made her think of him as now separated for ever from her family with a tenderness, a regret, rather in proportion, as she soon acknowledged within herself to his wishes than to his merits. She felt that his influence over her mind was heightened by circumstances which ought not in reason to have weight; by that person of uncommon attraction -- that open, affectionate, and lively manner which it was no merit to possess; and by that still ardent love for Marianne, which it was not even innocent to indulge. But she felt that it was so, long, long before she could feel his influence less. (Chapter 45)

Elinor is too easy on Willoughby IMO and she knows she is; it is unfortunate that Willoughby has so much charm and personal magnetism on the outside and be such a villain on the inside. I found Willoughby’s confession in Chapter 44 to be motivated by self interest and that even while admitting he is responsible he tries to justify why he was not really responsible or add an excuse to lessen his responsibility all the while saying he is not trying to defend himself. Willoughby’s character is weak; he never did the right thing although we are always made aware by his countenance that he is aware of what the right thing was but he could bring himself to do it—he always chose himself over others.

"Had they told me," he cried with vehemence, "that Mr. Palmer and all his relations were at the devil, it would not have turned me from the door. My business is with you, and only you."

I think if Willoughby had not already known from Sir John that Mr. Palmer was away from Cleveland he would not have ventured to go there. I do not see Willoughby facing anyone other than Elinor or Mrs. Dashwood or Marianne, women who he feels capable of swaying with his manner and charm. I do not see Willoughby willing to face a man who would despise him for his actions and to whom his charm would mean nothing—Charlotte did already say in Chapter 20 that Mr. Palmer would not visit Willoughby because he is in the opposition party. I am sure Willoughby would know if the family were at home he would not be welcome for this and his treatment of Marianne. I think Willoughby feels he can worm his way back into the Dashwood ladies good opinion if there are no outside influences.

"I understand you," he replied, with an expressive smile, and a voice perfectly calm. "Yes, I am very drunk. -- A pint of porter with my cold beef at Marlborough was enough to overset me."

Willoughby even lies about being drunk to excuse the impropriety of coming to Cleveland, he cannot even admit to the impropriety of visiting them without an excuse.

"I mean," said he, with serious energy, "if I can, to make you hate me one degree less than you do now . I mean to offer some kind of explanation, some kind of apology, for the past -- to open my whole heart to you, and by convincing you, that though I have been always a blockhead, I have not been always a rascal, to obtain something like forgiveness from Ma -- from your sister."

Does Willoughby ever apologize? I confess if he did I missed it! Willoughby’s confession is all about wanting to redeem him in their eyes, it is purely selfish. He has a lot of vanity IMO if he cannot stand being disliked for the terrible things he did—which IMO just shows how he does not want to accept responsibility. His motive of needing forgiveness is shattered right away as Elinor tells him Marianne has already forgiven him but he wants more than that. I think his real motive is that he wants to be reconciled to them so he has to show that he is not as bad as they think—in fact Willoughby does a good Poor Me routine. Willoughby goes on to blame “some distant relation” for tattling on him about abandoning Eliza not because what he did was wrong but because they want him out of favor with Mrs. Smith. He then blames Mrs. Smith for being offended at this behavior citing the “purity of her life, the formality of her notions, her ignorance of the world” as why he lost her favor instead his actions in seducing and abandoning Eliza. Willoughby also blames Brandon for making him look bad as if the story of his treatment of Eliza could be made to look better or perhaps Willoughby just hoped Brandon would keep it from the Dashwoods. He also basically calls Eliza a stupid tease, one he could not resist so that she can bear not only the blame of her own poor judgment but that of his lack of restraint also.

“Well, I went, left all that I loved, and went to those to whom, at best, I was only indifferent.”

Willoughby’s confession makes him look the worst villain to me rather than gentling his condition at all—I am not persuaded that he even loved Marianne when he decided to propose. He makes a lot of admissions but he never tells Elinor that he is in love with her. One of them is that he was only pretending to like the things Marianne loves and holds dear—it was all a big scam to make Marianne pay attention to him—he wishes to spend his time pleasantly. He admits to being “sincerely fond of her” and to having “affection” for her. What does “all that I loved” mean exactly? I think it means the good times and sincere affection he received from “all” of them. Willoughby felt good basking in the attentions he received from the Dashwood ladies—it was all about how Marianne and her family made him feel.

“But this note made me know myself better. I felt that she was infinitely dearer to me than any other woman in the world, and that I was using her infamously.”

How much weight does “infinitely dearer” deserve—we know of two women in his life, Eliza Williams and his wife Sofia and they are both so badly used by him that the “sincere fondness” he admits for Marianne would be infinitely dearer by comparison. He abandoned a pregnant Eliza Williams and has contempt for Sofia, telling Elinor that she deserves no compassion and practically wishes her death so he can have both wealth and Marianne: "Were I even, by any blessed chance, at liberty again." I think this is the ultimate callous and selfish statement and goes to show that he does wish to be in their good graces. He is IMO saying that now that he is rich he would gladly marry Marianne if he has the opportunity. I think this is yet another reason why he is so jealous of Col Brandon:

"But she will be gained by some one else. And if that some one should be the very he whom, of all others, I could least bear -- But I will not stay to rob myself of all your compassionate good-will, by showing that where I have most injured I can least forgive. Good bye; God bless you!"