Get a kitten or a puppy. My mom's puppy started insisting on curling up with me and, out of deference to the little guy, I catch myself resisting moving, so as not to to smash him or wake him up. Slept clean through the night a few nights in a row. I never sleep easily. Not in almost 60 years. I suppose, to some degree, sleeping with a significant other had similar therapeutic qualities but, over time, people are just bigger and you wind up fighting for covers and the like.