What is the very last thing you do before you settle in to fall asleep at night? (Or whenever you take your longest rest of the day.)
Iain and I keep the same schedule, so we go to bed together pretty much every night. We have a pretty standard routine, the order of which might vary slightly, depending on who's carrying out which task that night.
But the very last thing I do every night is tell Iain I love him. I'm not superstitious about it, and we tell each other "I love you" like a zillion times a day, so it's not some special thing we save just for bedtime. To call it a habit seems to suggest it's so axiomatic as to be meaningless, but it's not. It's a nice habit.