I've lived alone since I was 18, and am so accustomed to it that I find the continual presence of another an intrusion into my privacy and a curb to my independence. I've remained unmarried, and I know I'll never marry for this very reason. And though I've been in relationships and am in a relationship at present, I often wonder how long I can continue this way of life. I'm close to 47, my parents, whom I'm very close to though I live separately, are getting on in years, and I'm very scared that real loneliness will set in after they're gone.