The narrator turns to the Danglars’ home, where Lucien Debray visits the Baroness, asking what is on her mind after the events at Auteuil earlier that day. The Baroness says that it was nothing, that she is simply feeling faint, but she asks that Debray stay with her and read to her in the night. At this, however, the Baron comes in and tells Lucien to leave—that the younger man will have plenty of time to discuss matters with the Baroness the next day. Hermine is surprised, because typically the Baron does not interfere in her affairs so directly and brusquely.
The affair between Lucien and Hermine has been referred to for some time in the novel, but has not been shown “on stage,” as an event unfolding in the text itself. Here, however, their affair is again referenced only glancingly, when the Baron appears to acknowledge that he knows what has been going on, and that he wishes, contrary to normal procedures in the family, to spend some time alone with his wife.
The Baron then has a private conversation with Hermine in her chambers. He reveals that he has long known about her affair with Lucien, just as Hermine, surely, has known about his own affairs, and that they have decided to live “no longer as man and wife” for four years, only pretending to maintain a normalcy in marriage. Danglars says that this arrangement has been fine for him so long as he has not lost out financially. But the Baron strongly implies that Lucien, with his diplomatic connections in Paris, arranged the mix-up in the telegram that resulted in the Baron’s enormous financial loss.
The Baron seems to understand that someone has been behind the malfeasance with the telegraph operator. Of course, the reader knows that this bungling was caused by the Count, not Lucien, and so we have another instance of dramatic irony. Nevertheless, the Baron seems to sense that his fortune is under attack in some way, and he wishes to do what he can to preserve the money upon which his reputation rests.
As a consequence, the Baron says that he will not allow Lucien to interfere with his financial matters, and that if this should continue, he will ask Lucien and the Baroness to pay him back whatever amount of his own money is lost—that, in other words, he will not pay out of his own pocket so that the Baroness can have her affairs. The Baron also implies that he is aware of the Baroness’s earlier affair, when she was still married to her first husband. He seems to know, and not to care, that this affair was with Villefort, and that the Baroness had a child out of wedlock with him. Again, he simply doesn’t want these matters to affect his own life, and he asks that the Baroness behave with discretion with Lucien going forward.
This is an important revelation, as it sheds light on the Baron’s mind. The Baron seems not to be concerned that his wife has had an affair with another prominent society member, Villefort. This could be because the affair predates their own marriage – but by the standards of French society at the time, it would still be a blemish on both Hermine and the Baron for the romance to be revealed. In essence, then, the Baron tells his wife that, apart from whatever she might do with Lucien or previously have done with Villefort, he will allow nothing to stand in the way of his business, which he values above all else.