it actually depends on where you reside, what kind of society you belong to and which religion you follow. If you are from a place where gambling is a common occurrence, then i wouldn't worry about telling my girlfriend/wife or my family. Eventually they will know since it's very likely people around them gambles and they are aware of it. But if you are from a place where gambling is considered bad or prohibited by your society or religion, I wouldn't dare telling anyone. It'll be like telling everyone hey guys I'm a criminal, I do bad stuff. Now coming to my place, gambling is frowned upon here, so I'm guessing you got my answer. It's my personal business whether I do it or not...