It really depends on what qualities or traits you value in a partner and what traits you will tolerate to keep a loved one. I have a wonderful Aunt and Uncle who have been together for many years now and they USED to sleep together until she began to snore heavily and he began to have digestive problems resulting in loud belching noises. They still love each other dearly and snuggle when awake, but at night time they must sleep apart now to get the restful sleep they need.

I know another couple that works totally different sleeping cycles because of work. They make it a habit to set aside the time they have together to have a coffee and paper date at home. They don't talk at this time, they relax, read, sip coffee together and listen to music snuggling. The rest of the work week is spent leaving notes and riddles or jokes for each other's day.