It took MrS and I 3 years after we were married (7 years of being together) before we figured out how to actually say to each other what we mean (rather than expecting the other person to "mind-reader" us). (By the way this had nothing to do with poly.)
It actually takes practice.
Initially, we would act on what we thought the other person meant, then we would play the game..."you said 'x' I think you meant 'y' - did you mean 'x' or 'y'?" which morphed into "you said 'x', so I am going to act on 'x', even though I think you you meant 'y'." It's amazing, to me, how much actually acting on what people say causes them to consider their responses carefully.
Life was so much better as we learned to communicate effectively (again, nothing to do with poly). Why do we not learn these things sooner? Which is not to say that we never mess up. Sometimes people don't know how they feel... or they want to feel one way, when they actually feel another.
Life is a work in progress.
Me: poly bi female, in an "open-but-not-looking" Vee-plus with -
MrS: hetero polyflexible male, live-in husband (23+ yrs)
Dude: hetero poly male, live-in boyfriend (4+ yrs) and MrS's best friend
Lotus: poly bi married (to TT) female, "it's complicated" relationships with Dude/JaneQ/MrS (1+ years)
+ "others" = FBs, FWBs, lover-friends, platonic G/BFs, boytoys, etc.
My poly blogs here:
The Journey of JaneQSmythe
The Notebook of JaneQSmythe