In the text, it is inferred that B. Helmer's self-esteem is dependent on people believing that he is not influenced by his wife.
Helmer explains Nora how her interference in his decision of firing Krogstad would make him look ridiculous in front of his whole staff, as if he was a man with a lack of authority, externally influenced, who would have to deal with the unbearable presence of Krogstad in his workplace.