Wendy Troxel, senior behavioral scientist at the Rand Corporation and the author of Sharing the Covers: Every Couple’s Guide to Better Sleep, speaks with Vox about the benefits of sleeping apart.
We have a limited amount of research on this topic but it does show pretty clearly that people sleep worse while sharing a bed as compared to sleeping alone. But if you ask those people, “Do you prefer to share a bed with your partner or sleep alone?” most will say they prefer to share a bed. So there’s this discrepancy between what our objective measures show and the subjective experience of sleep quality.
It speaks to our social nature. Sleep is a very vulnerable state and we derive a sense of safety and security when someone’s next to us, and that feeling can actually facilitate good, healthy sleep. So in some cases there may be real psychological benefits from sleeping together that for many overwhelm the objective costs of sharing a bed.