There are different ways of looking at balance. If he buys you a gift for ten dollars and you buy him a gift for ten dollars, there is balance. On the other hand, if you both have separate accounts, you are a CEO of a fortune 500 company that he is a janitor at; you have five million dollars in savings and he has fifty dollars in savings - then, he spent twenty percent of his savings on a gift and you spent 2/10,000ths of your savings on him.

It is the same with emotions. Perhaps you are more capable of sharing things with an intimate partner than he is. Perhaps you have greater quantities of trust. Perhaps he shares things with you that cause him anxiety that is through the roof - while you sharing your most intimate secret with him only leaves you feeling marginally vulnerable.

If I had to guess, I'd say that I used extreme examples - but a lesser example would work as well. I have no secrets from my wife. She has kept secrets from me - but she does her best not to. Her best is good enough - it would be unfair of me to hold her to a higher standard that that.