A reader asked: "My husband and I have been together since 1976. We have not always lived together, and we haven’t pledged to be monogamous. But neither have we had an 'open marriage' or been promiscuous. An occasional fling when we have been traveling separately has been pretty satisfying. Recently I discovered emtricitabine out in the open in the bathroom. I looked it up and learned that it is generally used to fight the presence of H.I.V. in the system, or to prevent H.I.V. infection. I asked my husband why he had it. He accused me of 'snooping' and said he neither has H.I.V. nor is putting himself — and me — at risk. I confronted him again recently. I’m waiting for him to come up with an answer. We are no longer having intimate relations. But I would still like to know what information he is keeping from me, and why. Do I have a right to know"
