Common human problem: when two people sleep in the same bed at night, often one person will use more of the blanket. It’s not done on purpose. While sleeping, this person pulls more of the blanket around themselves, leaving less for their partner.
The partner wakes up because they’re chilly, but will have a difficult time reclaiming their fair share of the blanket. The blanket hog has the blanket wrapped around themselves or are laying on some part of it. And because of where they are in their sleep cycle, they are difficult to move or even to wake. It is especially difficult for the blanket-less person to do so because they are groggy and weak. And if they expend the energy to truly wake up and take back the blanket, they will have trouble falling back asleep. And might just lose the blanket again to the blanket hog.
The solution to this intractable problem?
Get another blanket!
Go to bed with a blanket for you and a blanket for your partner. Perhaps even a third blanket for good measure.
This also solves the problem of people who have different warming needs. One can have a lighter blanket and the other a heavier blanket.