Yep, not "almost" need to talk about ideas for the future, definitely need. It doesn't make sense to try to map things out too far, because who knows, but if people are operating with completely different ideas of where things are going, that needs to come to light sooner rather than later. More, and *clear*, comunication is pretty much always better with multiple relationships to juggle.
The goal here is to not let things get to the point where you're hurting so much and your relationship has changed so much that you have to ask A to choose -- K or you? That happens all too often in these types of vees that start as triads. Get things to a better, saner, more balanced place now before you let yourself get hurt so much that you burn out on the very idea of poly, y'know?
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.