In my apartment, I sleep on the left side of my bed. I sleep on my left side, facing the wall and I've always slept best that way. When I started dating someone and sleeping at their place, I slept on the left side of the bed, but on my right side facing him. It didn't take me long to get used to the change because he'd wrap his arms around me and I'd smell his chest and fall asleep almost immediately. And for the first few months, that was how I slept best.
Sometimes when we'd argue, I wouldn't feel as connected to him and I would turn back to my left side but we would eventually make our way back to each other in the center of the bed by morning. As time went on and resentments grew, the nights I slept on my left side started to outweigh the nights I slept on my right, until the last night, when I felt so much distance I had to sleep in another room to get any peace at all.
The following morning, I left when I realized I never saw myself going back to sleep in that bed.
Now I'm in my own bed, on my left side, facing the wall.
Wide awake.