If you kill the husband in order to get the wife, you thereby become the husband and she stops making love to you.
I get the point. Husbands of the world, rest easy in your beds! You need fear nothing from me, at least not on your lovely wife’s account. Other things, maybe.
In this book they actually did get married, but that wasn’t necessary. The bond between crime partners subject to the guillotine is like the bond of marriage, except that you have to take it seriously.
And also: whenever you’re together you will sense the presence of the clammy, decomposing corpse of your drowned victim, who will also haunt your dreams. I knew about ghosts already already, from Strange Stories From a Chinese Studio, Saxo Grammaticus, The Golden Ass, and Njal’s Saga, but it’s nice to have confirmation from a modern scientific source.