This is true. The current life you are experiencing is the extension of your soul participating directly in the material form you inhabit as a physical human. You are constrained and held within this plane of existence by the energies of your creation. You cannot dematerialize and go somewhere else. Your soul is more mobile; that is to say, the consciousness within you that is a soul extension that leaves upon physical death can go out and about on its own through astral travel, for example, but that is a different matter. The soul extensions on other timelines are an aspect of your soul living in parallel in those other dimensions and will continue to exist as such, keeping in mind there are loopings of time with an exchange of some energies back and forth among the soul extensions in play existing simultaneously, and those that have been on other timelines that may have ended and are not overlapping.
So this crosstalk that can happen will of course be moot with your passing at the time of physical death. Your soul extension participating in the current incarnation will journey through the lower astral plane in an attempt to return to the higher astral plane where you originated. You will not go to other timelines to join up with a life unfolding elsewhere by another part of your soul. So these are discrete events, circumstances, and unfolding experiences that will influence you indirectly but are discrete and separate in most respects. The way they impinge on your current existence is largely through the akashic records because there is a sharing and registration of all parts of the soul as new extensions might be created to take on new adventures and explorations. These will influence one another to some extent in a similar way as you influence all your brethren within the human family, at least indirectly, in addition to physical encounters and adventures you might engage in. So there is a large interplay of energies going on continuously among dimensions in the varying levels of the soul, exploring and experiencing an ongoing learning and growth that is the purpose of creation to unfold.