I am a thinker tinkerer - someone who takes things apart mentally to see how they work. My wife doesn't care how something works, as long as it works - so she doesn't spend time and effort trying to see how it's constructed. Each approach works for each of us. I don't try to get her to examine the details, and she puts up with my analytical mind. I find a way to make it work, while she allows it to work as is. Together, we make a really good pair, since we don't expect to approach anything the same way - but both of us are focused on the fact that it works in the end.
I hope that isn't painful for those who are at odds with their spouses. It's just how my wife and I are, but I think the general principle of recognizing that all of us see things a little differently is important. If all members realized that, I think there wouldn't be a need to worry about being treated differently or have "secret worlds" in which we live. We would be much more open with and protective of each other. However, that recognition is not an easy thing - and differences can be scary and insecure; hence, secret worlds.
For what it's worth, although I don't feel like I have the type of secret world I have heard others describe, I certainly don't share all of my opinions and beliefs with everyone - since I know not everyone would be able to accept them. I have certain help I can provide due to my callings over the years, but, in the performance of those callings, I have to be very careful sometimes in order to be accepted as someone who can help. I still correct people when incorrect doctrine is taught or espoused, and I still share thoughts and ideas that definitely are outside the mainstream, but I have to be very, very careful how I do so - simply given the fact that I have not represented myself in many meetings I have attended in my life.
So, in a very real sense, I do have a "secret world". In my case, however, I accept that as an unavoidable aspect of my callings, so my secret world is different than most others.