Always looking for someone

It's in my profile, the story of my friend whose 6 year old daughter had died. "I've got four other kids," she told me, but "I feel like I'm always looking for someone."

It's the perfect phrase to describe one's empty nest. Even now, nearly five years after the first one left, nearly two with both of them gone, I find my radar sending out signals-- where are they? Are they safe?