"May contain traces of boyfriend."

"I can't do this," she says, pulling away.
"Why?" I ask.
"I've got a boyfriend."

So, this is the conversation that marks the end of so many of my dates. It's become as familiar to me as picking up the cheque, saying goodnight and poking on Facebook. (It's usually the only poking I do that night.)

And it's making me wonder what it is about me - or my dates - that makes this conversation so familiar. Do they think I'm gay? A "Will" to their "Grace"? Are they shopping for a new boyfriend (but "just browsing, thanks")? Or, like Schrödinger's cat, does the boyfriend only appear at the end of the date, when I take a gamble and try to open the box (so to speak)?

In any case, it terrifies my friends in relationships. "It makes me wonder what my girlfriend was really doing on Saturday night," my housemate says. "Come to think of it, what were you doing on Saturday night?"

Well, I was probably having that conversation, like a disclaimer tagged onto the end of a radio advert, muttered quickly and incomprehensible, a list of possible side effects - "may cause mild embarrassment, sudden loss of date and that sinking feeling that this is all too familiar..."