Note that all sorts of developments can happen. You may break up. You need to ensure you are trusting a person who will not divulge your sensitive information after a break-up. Not everybody can be trusted this way. It sounds like your bf is a really good guy, but just make sure. Since many relationships eventually lead to a break-up of some sort, you need to think about what will happen post that hypothetical break-up. Again, he sounds rather nice, so it is just a statement of the general advisability of being cautious.