Wintering Cuban Oregano Indoors

A couple of years ago I bought Cuban oregano from you. I have been bringing it in every fall but usually at least half of it dies within 3 months of coming inside. So far I have always had at least one healthy plant to start cuttings from in the spring. Any ideas on why it would die? I bought it because it is supposed to help control earwigs. I don't really know if it does or not but I would like to keep a couple of plants anyway. Any suggestions?

For the winter the plant should be kept cooler and drier, but in as good a light as you can give it. If it rots you may have to supplement the sun with some fluorescent lights.