It is important to remember what has just happened in this Act in order to place the hand delivery of this letter in context. Torvald has just opened the letter that Krogstad has sent to him telling him about what Nora has done and how she has been deceiving him. After initially responding in rage, Torvald expresses his opinion that everything needs to be "hushed up at all costs." At this point, it is clear that Torvald is just going to do his best to cover up Nora's misdemeanours and not do anything about the more serious problems that lie underneath. Initially, when the Maid enters with a letter for Nora, Torvald snatches it and opens it himself. Yet note how he responds when he reads the contents:
Nora! I must read it again. Yes, yes, it's true! I am saved! Nora, I am saved!
Even though Nora ironically questions him about whether she is included in his statement, the initial response makes it clear that Torvald is just a selfish man who only thinks ultimately of himself. Even though it is his wife's fault, he sees it only as impinging on his own good name and reputation. He clearly cares nothing for his wife, and this is revealed through his declaration that he, and he alone, is saved with the news that Krogstad does not intend to blackmail Nora any further.