Southworth was really quite good at having human characters - she, as the author, never really condoned any losses of virtue (which, albeit, weren't many, but were present, and sometimes they were willing) but also never preached against it, either overtly in the writing or by visiting bad consequences upon them. Definitely not at all like, for example, Moll Flanders, which was preaching all the way.

I read another book last summer which treated with the subject of infidelity in a very touching and rather modern fashion, East Lynne by Mrs. Henry (Ellen) Wood. It was one of those books which as you read you think, wow, this would make a fantastic "Pride & Prejudice" style movie. The publisher's summary of it is:

"This book looks at the anxieties of the Victorian middle classes who feared a breakdown of the social order as divorce became more readily available and promiscuity threatened the sanctity of the family. In this novel the simple act of hiring a governess raises the spectres of murder, disguise, and adultery". Definitely recommended.