My sarcastic answer used to be “Because something is obviously terribly horribly wrong with me, but none of my friends have the heart to tell me what it is.” But then, like DianaG, that kind of flip answer made me realize that people don’t get irony or self-deprecating humor and then I get a lesson in self-esteem. So I just use the “Oh, I know, right?! Who knows?”
Recently, a second date actually asked me if I was afraid of commitment. I told him I simply don’t see the point. That’s the serious answer: I’ve been so fiercely independent for so long that I can no longer figure out why I’d need to be married. I just don’t get it. You can have a long-term, monogamous (if you so choose), perfectly committed relationship without ever getting married, so I can no longer think of any good reason to do so. I figured if I’d wanted marriage badly enough, I’d have done something to make it happen by now, but obviously it hasn’t meant that much to me, so… still single.
Well I did, once. On a dating site, some guy messaged me and was astounded that I was single, and wanted to know why. “Um, because I never got married?” I spent about an hour (before I finally put him on ignore) trying to re-answer the re-phrased question. He just. couldn’t. understand. it.
I have heard several times: You’re XX age and have never been married, what’s wrong with you. I have always responded with: You’ve been married twice - what’s wrong with you.
(Oddly, no one who has ever asked me that was only married once.)
I think it’s interesting how the general assumption is that being single is something that happens TO someone instead of something that someone would CHOOSE.