Peter Ruff and the Double Four by E. Phillips Oppenheim

Bernadine, sometimes called the Count von Hern, was lunching at the Savoy with the pretty wife of a Cabinet Minister, who was just sufficiently conscious of the impropriety of her action to render the situation interesting.

"I wish you would tell me, Count von Hern," she said, soon after they had settled down in their places, "why my husband seems to object to you so much. I simply dared not tell him that we were going to lunch together, and as a rule he doesn't mind what I do in that way."