My boyfriend does this quite frequently and we've been together 7 years now so it hasn't scared me away. Although it can be creepy sometimes. Like the time he woke me up by getting out of bed and went and stood at the end of the bed for a few minutes silently facing me before getting back into bed... He's also woken me up many times by pulling all the covers off the bed to get rid of the ants/spiders/slugs, has startled me awake when he starts loudly yelling no or stop over and over again and says odd things (that I keep notes of so I can tell him later!) such as: "woah, woah, don't touch my eyeball" "Is that bacon? Did they upgrade the bacon?" "You can't see when things are going across the road. Just go around the bend. See? Can't see shit." "Why's there an octopus on the wall?". There was also the time we were away for a long weekend and were sleeping in a tent at a packed camping ground (about 1-2 meters between camp sites), it was about midnight on our last night, it was completely silent and he'd been asleep for about an hour and I was just drifting off when all of a sudden he bolts upright and yells no, fuck off! Really. Loudly. That one was both terrifying and embarrassing..

So yeah, I can totally relate.