I sleep on the right (left side if looking from the foot of the bed) always have and when I was pregnant it worked perfectly as I used to always sleep on my right side which meant my belly was close to the edge - which was essential with the twins as I had PUPPS so used to sleep with my belly uncovered to try and keep it cool and stop the itch.

I now 90% of the night sleep on my right side so face outwards, I can't stand sleeping in towards the middle of the bed or having someone touch me when I'm asleep so being on this side means I can sleep my preferred way and also creep across to the edge if my personal space gets invaded