To re-iterate what Opalescent said, make it a habit to keep everything that happens in the bedroom completely and utterly private. Granted, some people may be voyeurs and enjoy hearing stories, but usually the reasons for wanting to know are not good ones. Knowing something is likely to trigger insecurities, force one into making comparisons, and bring up a lot of "why don't you do that with me?" type questions.
Plus, there is such as creature called privacy. I may be her husband, but my wife is entitled to her privacy, including any intimacy with her lovers.