Separate comforters
In Scandinavia, I've noticed that beds, which are intended for two people, often have a single fitted sheet with two separate comforters - one for each person. For a queen-sized bed, there are two twin-sized duvets that are folded in half and laid side by side. While this was strange at first, I wish more of the world would adopt this.
Why do I assume that sharing a bed would mean that people would share a blanket? There's no good reason for that other than that's what I'm accustomed to. When sharing a bed, I often find myself either too warm or too cold and it's frustrating to wake up to find my partner having "stolen" the blanket. But, by having individual comforters, this is no longer a problem.
I'm looking forward to taking this fittingly simple solution home with me.