My husband and I have been together for almost 20 years and had always slept together except if I had a cold or something and was coughing a lot.
Well, about three months ago it was pretty hot at night, and he wanted to keep the window open all night. I'm a light sleeper, and I could not get a good night sleep because of birds singing or cars going by, so I slept in the guest room. Y'all, it was the best sleep I'd ever gotten! Anyway, the weather remained hot, he enjoyed the fresh air, every night he'd sleep with the window open, and every night I'd sleep in the other room. Next thing you know, months had gone by.
Anyway, to make a long story short, at first it felt weird. But then it became kind of fun. We'd "visit" each other but still sleep separately. I loved it! I could sleep on my back and snore if I wanted to. The guest room is really dark and quiet, just like I like it. I even started looking more well rested. So it became our normal routine to sleep separately.
Fast forward to today. Well, winter is now here, and the window is no longer open. Just last night he told me, "Hey, there's really no reason for you to sleep in the other room now that the window's closed." So we'll probably go back to sleeping together some of the time. But if I feel that I need my little cocoon room, I will not hesitate to go sleep alone.
So my final conclusion is that two people can have a healthy relationship and still sleep separately!