When we were younger, it was harder to stay mad for a long time when we slept in a double bed together!
Or - to put it another way - with a king sized bed, the distance between a couple can get longer and colder as time passes!
We can manage in a double - but I do prefer at least a queen -sized bed for sleeping now. But sometimes the couch is okay too if I'm having a really restless night.
I used to think it was AWFUL when (usually older) married people slept in separate beds.