Leaving someone you know well requires the body to adjust to loss. There's no way I know to avoid this very basic grief. I don't know that I'd want to.
Reb Anderson used to caution students against sleeping together (including "just" sleeping together) on the grounds that it connects people in ways they may not be ready for. Even if you're not in the same bed, sleeping in the same room with others will put you in synch: entering into consciousness in the morning; drifting into oblivion at night; continuing to be alive in the nonexistence of deep sleep. What are we when we sleep? What has become of the mind, of the "self" that rules the waking hours? Nobody can say, but the breathing bodies resonate anyway, together in a realm deeper than mind or thought.
You know this in the monastery: you can wake up at 3:50 a.m. because everyone else is doing the same.
Leaving the people you sleep with is hard; it disturbs something in that very deep realm, and on the surface there is a feeling of loss, or grief, or anger. We don't know who we are, and part of ourselves is moving to another place. We will sleep in the company of unseen neighbors, in silent buildings hundreds of miles apart. We don't know who we are, and we don't know what we are shaped into by the other lives that invisibly meld into ours.
