The joke that depends on a confidence is too expensive for the laugh it earns.

A private detail makes a joke land precisely because it is private. That is why the cost falls on someone who is not choosing to pay it, usually in a room where they cannot object without making the moment larger. The laugh lasts a few seconds. The lesson that things told to you may reappear as material lasts a great deal longer.

Before the funny line, check whether it still works if the person is absent from it. If it needs their secret in order to be funny, keep it. If you have already done this, say so to them directly.