Hi. I have a Garmin Vivoactive, similar to a Fitbit. I use it with my iPhone, but I'm pretty sure it would work without a smartphone by just syncing it with the website when you plug it in to charge it. Not certain, though.

This is what the sleep data looks like:



It's pretty uncanny. It almost always picks up the exact time I fall asleep, wake up, and toss and turn. I just keep it in the back of my mind if I was awake at some point holding very still, and it thinks I was asleep. I'm not sure how useful this is when your issue is breathing and/or snoring, though. Maybe get a model that measures heart rate? Mine only does so with the chest strap, and it was a hassle trying to get it to take the data all night.