Is Henry Crawford a sadist, a seducer or just misunderstood?

In volume 2 chapter 5, regarding Henry Crawford:

With a significant smile, which made Fanny quite hate him, he said, "So! Rushworth and his fair bride are at Brighton I understand - Happy man!"

What does the significant smile mean? Has he shagged Maria Bertram?

Fanny thinks Henry Crawford has toyed with the affections of both Maria and Julia Bertram. I find it difficult to say for sure. Fanny seems to think that Mr Crawford deliberately messes young ladies around. Is he a bit of a sadist? Surely, a young gentleman could be charming to young ladies without being expected to commit himself to marriage, even then.

The next chapter spells it out.