I've been thinking about the fact that some readers of Sense and Sensibility don't believe Willoughby truly loved Marianne, even though everyone in the book believes it and the narrator makes it clear how much he cared for her, at the end. And I think this reading of him takes away from one of the messages of the book, which is that love is not enough.
Willoughby loves Marianne, but that's not enough to stop him from hurting her, it's not enough to make him give up his cushy lifestyle and marry her, and it wouldn't have been enough to keep him happy with her long-term. Marianne loves Willoughby, but it wouldn't have been enough for her to be happy with him long-term either.
Edward loves Elinor, but that's not a good enough reason to break his promise to Lucy, because integrity and honor and responsibility are just as important to him. Brandon loves Marianne, but that's not reason enough to court her, because he knows her feelings lie elsewhere and she doesn't respect and esteem him yet.
Love is important to all these characters, and is a vital part in making the marriages that they ultimately end up in strong and happy, but it's not the only thing that makes them work.
Of course, Sense and Sensibility is hardly the only Austen novel to make the point that you need more than love or romance or passion to make a relationship work. But I think it's interesting how we get to see this play out in the villain of the novel. Willoughby does some truly horrific things, but his character shows that even really bad guys are capable of feeling love and guilt and remorse. But none of these feelings are ultimately strong enough to change him. Because love is not enough.
