When my boyfriend and I decided to move in together, he assumed that I'd be getting rid of my now-redundant bed and start sleeping in the same one with him every night. But I was hesitant — there was plenty of space in the second bedroom, and I kind of wanted to hang onto my bed (especially in the case that our hasty cohabitation decision turned out to be a disastrous one, but that's a story for another time). Happily, my ever-reasonable boyfriend was amenable to this proposal, and so the bed moved with me into our cohabitation domicile.
It's hard to find exact figures, but estimates in Canada, England, and the United States indicate that anywhere from 25 to 40 percent of adults in married and/or cohabitating couples routinely choose to sleep apart (the estimate is even higher in Japan). Why is sleeping together our default configuration in the first place? Historically, there were periods in time when many or even most Americans slept apart. Apparently, Freud came along and ruined everything — not sleeping well in the presence of your partner must mean you subconsciously hate him, or something.
Luckily, we have real science to refute that suggestion: sleep studies show that couples sleeping together very often fail to reach the deeper stages of sleep, because each member is being constantly, however slightly, disturbed by the other. This is even assuming that you're getting to sleep, and staying asleep, for enough hours together in the first place — different work schedules or circadian rhythms can make this a challenge.
In my case, I'm a night person and I have two sometimes-annoying dogs, while boyfriend works very long hours beginning early in the morning. At first, I figured I'd sleep alone a couple of nights per week, especially those before his extra-early mornings, but actually in the past six weeks I could count the times I decided to co-sleep with him on one hand.
Here is my bed (please disregard previous tenant's hideous green walls). It is delightfully strewn with excessively many pillows and all manner of bedding, as my cold-blooded self sees fit. I keep my candles and book and lotion and medications within arm's reach. The dogs sleep soundly in their own bed right next to me. In short, this arrangement is heaven.
Do I sleep in there because I'm mad at my boyfriend? Not in the slightest. In fact, all this higher-quality sleep could only make us more pleasant and agreeable people. Do separate beds and separate rooms keep us from spending quality time (of whatever kind...) together? Nope. Walking across the apartment isn't exactly some huge, burdensome barrier to seeing each other. Furthermore, I like the way that I haven't gotten used to spending 6+ hours per day in very close physical contact, so that now when we're close it feels really, really good.
There's no need to switch to sleeping separately if co-sleeping works for you, but there's also no reason to feel guilty or apologetic if your needs are different. Explain to your partner up front that it's nothing personal, and you can forgo many restless nights, tired days, and petty arguments. Save that emotional energy for the more difficult domestic and relationship compromises that can't be avoided via a simple logistical fix.