When I was travelling the world in my Olympic persuits I often shared a bed with a teammate. (Purely platonic, I promise.)
But we always had two duvets on the bed which I just thought was an arrangement they made for us because they knew we were sharing a room.
Now whenever I was sleeping around with people in North America (Wait...that totally came out wrong.) We invariably had one large duvet or blanket on the bed that covered both of us until morning. I'd sleep great. She'd be complaining that I stole all of the covers.
The Biggest Cause of Sleep Disturbance
If I sat in a chair while you slept and tugged at your covers all night you probably wouldn't get a really good sleep. But we tend to blame the mattress for most of our sleep issues when sleeping with a partner. The truth is that the tug-o-war with the blanket is more disturbing.
In Europe, having two people sleeping with two Twin sized duvets is the norm. In North America it seems weird. I have no idea why. But my wife and I have been sleeping with two twin duvets for years and the tug-of-war is over.
And it's not just the wrestling match for the covers that's disturbing. Has your wife ever let a SBD under the covers!!! (It happens alright. No matter how beautiful they are.)
So when my wife and I get into bed at night we read a bit. Then perhaps a little snuggle. Then we return to our separate sides of the bed where she has a Classic Weight duvet and I have a Winter. (Or maybe I stole hers, I can't remember). Where we then drift off into our own separate sleep environments. No tugs. No oh-my-god-how-are-your-feet-so-cold moments. Although I will let her snuggle those cold toes over just for a little while to warm them up for her.
Sleeping with two Twin duvets on the same bed can be an absolute game-changer for couples who are sharing a bedroom and a bed. You may find that the mattress you've been complaining about for years really isn't the problem after all.