*Quoteunquote-do you and your dp not have any separate friends either?
This might be a wild stab in the dark- but are you by any chance members of a kibbutz or something like that? Or some other closed/semi closed community*
sorry Seeker that made me snork smoothy all over my key board,
some might say where we live is one big alternative community, 
Of course we have separate friends,
skimming through the thread it seems that others who are in long term relationships have the same arrangement, maybe it works never having anything unsaid,
I can almost guarantee that if a friend has something occurring in their life they will head over to ours to share,
I'm very open about my life experiences, so most people find me easy to talk to, as is DH,
I did have a Quaker upbringing, secrecy would not be encouraged.
I'm also high functioning Autistic, so I can't handle lying, or misleading people, I like to be straight forward in all dealings, if you ask me something you are going to get an honest answer, all my friends appreciate that, so they tell me.