Hi everybody,
I have the same thing. My body temperature rises when I fall asleep. If I can't get warm enough, I can't fall asleep. But I only noticed how warm I get, after somebody else mentioned it to me. I don’t kick my covers off and I don’t wake during the night.
Sorry, I don't have any answers either. It’s very likely, that there is more than one possible cause for this. But I think, that people, who get warmer when they fall asleep often have cold hands and/or feet, love long hot showers and have less problems during hot summer days than in the winter. Does this apply to you (your spouse/boyfriend/…)? Because it definitely does for me.
I don’t think that this temperature rise is a fever that the body uses to fight infection. That would mean that we are permanently fighting some infection for the last x years.
I don’t want to believe, that I have a tumor in my head either…
One of my theories is (in case this does have something to do with cold hands and feet), that the body needs to raise the temperature of the hands and feet so they are as warm as the torso, or maybe even warmer. And after they are warm enough, maybe the torso starts to cool down.
Did anybody try measuring the temperature of the torso, the hands, in the mouth, maybe even in the rectum at different times? To see how the temperature evolves when we start to fall asleep and when we sleep. Even better would be a thermo-picture, if one could borrow a thermo-camera somewhere.

I’ve been planning to do this for a long time, but never really tried it.
What is your experience?
As many others I’m really glad I found this discussion. So if you find any info on this topic, don’t forget to post it here.