I realize that you think it's just in the spirit of fair gamesmanship ("hey we're all on this together," and "I'm such a good sport about this"), but you might as well sip your pinot grigio and ask, "So, who else are you currently fucking? How's that going?"
I am convinced it starts innocently enough: a little conversational wind-up, some basic throat-clearing before you plow on to more interesting topics. You also might be genuinely curious. But when you ask this question, you break the romantic spell. You call uncomfortable attention to the obvious: "I know I'm not the only one you've met on there." And it just doesn't need to be said.
There just is no right answer:
"Oh, it's going great. I've had so many dates. Who knew that getting laid could be this easy?"
"It's terrible. No one will write me back."
"It's hard, because most guys are such assholes."
You either sound like you don't really need to be on this date, or that you need it too much, or you come off sounding like a beleaguered, judgy prick. It's a lose-lose. It also puts you in a tempting position to denigrate those who've come before this date, and it's an uncomfortable foreshadow ("What will he say about me tomorrow?"). Save the dishing and piling on and other fun nastiness for your friends.
Case in point: A guy I met on OKCupid a few years ago asked me what I thought of the site. When I gave a vague response, he jumped in to tell me how horrible it was: "The women in New York City are such gold diggers, always making you pay for shit."
We were at a tea shop at the time, and when the check came I whipped out my wallet so fast -- I felt pressured to prove that I Wasn't Like Other Girls, and certainly not attempting to work him over for an earl grey. But he was all, "Nah, don't worry about it. I got this." The whole thing left a bad taste in my mouth. He only had bad things to say about the women he'd met. And yet the only thing they had in common, as far as I knew, was him. He texted the next day; I never wrote back.
Asking how your date is faring romantically is the fastest way to suck the sexy tension out of the room. If you wonder why your dates feel more like interviews, it's because you're treating them like a job fair. ("Got any good prospects?")
I'm all for honesty, but not to the extent that you let fly your wrath or judgment or even mild disappointment -- directed at an entire gender, population, or unfortunate dates. You risk painting yourself the bitch, the dick or the victim. And none of that looks good on you.
Plus, in all honesty? It's really none of your business. I say that in the best way possible. It literally isn't -- so why burden yourself with more info than you need at the moment? Just because you're sharing tapas with someone doesn't give you access to their entire personal backstory, nor do they have access to yours. It's a date; it's a time to be choosy, and to ask questions you really want the answers to.
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