You've probably heard the explanation before. They just haven't found the right person yet. When the right one comes along, they'll know. The commitment problem isn't really a commitment problem; it's a person problem.
This explanation is rarely accurate.
The nervous system that can't close the last distance in a relationship isn't waiting for someone worth closing it for. It's maintaining the one protection strategy that has always kept it regulated. Before the label, before the official commitment, before the conversation that makes the relationship real in a way that can't be undone, the exit is still technically available. And available exits are how this nervous system stays safe.
This isn't selfishness. It's architecture.
The nervous system that keeps exits available learned to do so somewhere before this relationship, probably long before. In an environment where full exposure produced outcomes it couldn't manage. Where closeness arrived with cost. Where the people who were supposed to be safe weren't consistently safe enough for the nervous system to stop monitoring the exits. And so it didn't. And so it still doesn't.
What this produces in adult relationships is a specific pattern: genuine warmth, genuine care, real investment, and a persistent refusal to formalise what the relationship is. The behaviour says one thing. The label keeps not arriving.
From the outside, this looks like ambivalence. From inside the nervous system producing it, it feels like wanting and not being able to. The wanting is entirely real. The inability is also entirely real. Both things are true at the same time.
The shift doesn't come from finding someone worth committing to. If it came from that, the pattern wouldn't repeat across multiple people who were genuinely worth it. The shift comes from accumulated experience of closeness not producing the cost the nervous system was built to expect. Enough instances of the exit not being needed. Enough times the warmth stayed. Enough evidence for the nervous system to start updating its model of what full exposure actually costs.
The exit becomes less necessary when safety becomes more credible. Not through deciding to be different. Through the nervous system finally receiving enough data to build a different prediction.
If you want to understand what's driving this dynamic, on either side of it, Know Your Attachment is where that understanding starts.