William Le Queux (1864–1927)
The White Lie (1915)

An honest girl unwittingly marries a scoundrel who is part of a criminal gang. Eventually she learns the truth. But how can she avoid bringing dishonour on her second husband?
There’s a sub-plot with German spies, a bunch of burglars and con-men, and some romance in this tightly-plotted story.

The source was Project Gutenberg.