They have significant differences in temperament, as seen in their two attitudes toward money and toward living according to laws and social rules. Gender roles exaggerate those differences because Nora is unable to have a profession so she could risk being extravagant with her own income.
Nora and Torvald also do not engage in the kind of direct communication that would probably accompany a relationship of equality. He talks down to her by excessively using pet names with the word little in them and talking to her in the third person. He clearly has no confidence that she can manage money in any circumstances and assumes he can control her only by doling out money to her in limited amounts. Yet he is unaware that she has forged a loan that defies all his financial and social principles. He is oblivious to her complexity and depth, never imagining that she would overtly go against his dictates.
Nora is perfectly willing to play her part in their indirect communication by lying to Torvald and pretending to agree to his dictates. She also coyly asks him for favors in order to play on his ego as the loving husband:
NORA (Playing with his coat buttons, and without raising her eyes to his): If you really want to give me something, you might—you might—
HELMER:— Well, out with it!
NORA (Speaking quickly): You might give me money, Torvald.
Nora also falsely justifies her own misdeeds because they are meant to achieve positive goals. For example, she forged the signature on the loan for her husband's sake, so she can't imagine it really being a bad action to take or one that will bring serious consequences