[McWobbleston]

As someone who used to regularly fall asleep to TV, it wasn't just a learned behavior. I have a very overactive mind without stimulus it tends to get to work, but with something like TV sitcoms I'm not particularly interested in my mind empties and lets me get into a sleep mode. Despite not having a TV in the bedroom for years I still have issues if I try to go lay in bed right away, so it may not be so simple for OP

What I've learned helps me is watching TV / listening to music while laying on the couch, and moving into the bedroom with a dim light once I feel myself drifting. Still, I often fall asleep next to the TV, but its better than tossing and turning half the time until I have to take melatonin to force my body to fall asleep