I have such trouble falling asleep at night when sleep alone?

Sleep hygiene: Make it a lifetime habit: 1) Keep a regular sleep schedule (same time in/out of bed), 2) quiet, dark room - no TV/music, 3) use bedroom only for sleep/marital relations, 4) if no sleep in 20min, leave room until sleepy, then try again (repeat as needed), 5) No caffeine after noon/no alcohol at bedtime,6) Write worries in a journal by bedside, & deal with them next day.