Dragging others along for the ride.
When beginning the journey into poly, the mantra is tossed at one constantly: Communicate, communicate, communicate! So there is talking, chatting, conversation, discussion, notes, perhaps even a bit of mime when words fail, all in the attempt to COMMUNICATE. There are differences in processing speed to account for, changes in perspective as experiences shift viewpoints, and even more importantly, the desire of all involved parties to share information in a way that is understood by the others they are in connection with, to contend with.
So what happens when one person isn't as interested in communication as those they are bonded to? Can a good relationship dynamic survive a degree of apathy within the structure?
I once saw a large spider making it's way across the floor of our kitchen. It was moving at a very slow pace, and after taking a look, it was apparent why that was. The spider had attached itself to a large dust bunny from underneath the refrigerator, and was forced to drag that weight across the room with each step.
There are numerous examples I've heard over the years I've been exploring poly where the non-communicative partner was able to drag the whole thing either to a screeching halt, or into total ruin. Not so much from the lack of communication, but because of the fatigue on the part of their partner(s) exerting themselves to keep the communication train rolling.
It's tough enough being responsible for self-disclosure without expending the energy to delve into another and pull communication out of them. The sheer amount of effort involved in exposing the heart and mind of another is truly boggling. Yet, repeatedly, I see the attempt being made to do so on the part of a well-meaning partner. Never seeing the degree to which they enable the "lazy" communicator to never learn strong skills that will lead them to be a true "partner".
Yes, some people are just more private, slower to trust, quiet, shy, damaged in some way, unpracticed, introverted, or whatever reason one would prefer to attach to a lack of drive to communicate. At what point do those things become an excuse? At what point do we cease to accept the excuse and request the effort that we are willing to put forth on our own behalf?
If communication does not come from internal motivation, it will not be sustainable over time. By all means, teach skills, tools, demonstrate by example what you wish to receive, but be wary if you find yourself trying to "open someone up", as it can be a form of passive-aggressive control on the part of the reluctant partner. Certainly not something to reinforce and feed in any relationship.