I can’t tell you how many times I had ended up with little to no blankets after sleeping 4 four hours. Eventually, spouse and I decided that we would get two full-size blankets for the bed so that we could each have one. This has prevented so many restless nights.
In some countries, Germany, Sweden, etc., people have been doing this for a very long time. 1 bed 2 duvets.
And it remains a mystery to me why anyone would want to share a blanket (other than for cuddles).