A Grotesque Romance

A  niece of mine recently had her class read The Invisible Man by H. G. Wells, and she wrote to ask me why I thought the novel was subtitled "A Grotesque Romance" as it certainly wasn’t a love story.  I hadn't read the book, but I did see a film version.  The question intrigued me, though, so I did a little research and came up with the following:

According to Wikipedia, "The romance novel is a literary genre developed in Western culture, mainly in English-speaking countries. Novels in this genre place their primary focus on the relationship and romantic love between two people, and must have an emotionally satisfying and optimistic ending."

Romances are generally love stories, though the category has sometimes been stretched to mean love of adventure, ideas, inanimate objects, non-human animals (in the non-ick sense of the word love. The other kind of human/animal love is classified as porn.), etc.  So I think the subtitle "A Grotesque Romance" may be intended to classify The Invisible Man as the story of a twisted love affair that has an unhappy, if not unsatisfying, ending, i.e. an egotistical man's love of his own idea gone horribly awry. (Basically extreme egophilia carried to an illogical extreme.)

Not having read The Invisible Man, I can't say whether the main character, Griffin, is in any way a sympathetic or noble figure, or if the novel rises to the level of a literary tragedy, but The Invisible Man seems very similar in theme and moral to Mary Shelly's Frankenstein. (The title of which is the name of the egocentric doctor who created the monster, not the name of the monster itself.) Frankenstein is a classic tragedy of a good man whose ego got the better of his common sense and humanity.  The Invisible Man seems to have the same disorder.

That's my take anyway.  Someone must have read both novels and formed an opinion on the subject.  What do you think