The couch carries no performance pressure; your bed has accidentally been trained to mean effort and frustration.
Sleep pressure does its job on the sofa, while in bed the act of trying to sleep keeps you alert. The retraining rules come straight from NHS insomnia guidance: only go to bed when sleepy, keep a fixed wake time, wind down for at least an hour before bed, and keep the bedroom dark and quiet. If you are lying awake, get up and return when drowsy, so bed stays associated with sleep. Late couch dozes drain the sleep pressure you need at night. Long-running cases respond well to CBT for insomnia via your GP.
What to do
Common questions
Why do I fall asleep on the couch but not in bed?
This is one of the most common insomnia patterns, and it is about association, not comfort. On the couch there is no assignment: you are watching something, sleep pressure builds, and you drift off. In bed you are trying to sleep, and trying is stimulating; your brain has learned that bed equals effort, clock-watching, and frustration, so it stays alert there. Sleep medicine calls this conditioned arousal, and the fix is retraining the association, which is exactly what NHS insomnia guidance points at: only go to bed when you are sleepy, keep a fixed wake-up time every day, relax for at least an hour before bed, and keep the bedroom dark, quiet, and cool. The behavioral rules that matter most: do not lie in bed awake for long stretches; if sleep is not coming, get up, do something calm in low light, and return when drowsy, so the bed never becomes the place you lie frustrated. Keep couch naps short and early or skip them, since a late couch doze burns off the sleep pressure you need at bedtime. If the pattern persists for months, ask your GP about cognitive behavioral therapy for insomnia, which the NHS lists as a treatment.