Yes but in life as in dating, I'd like to know why I'm not a match.

Knowing the posting was inaccurate for what you're looking for is better than wondering why one got turned down for what seemed a perfect fit.

Instead of asking "what went wrong", maybe you might want to ask "is there anyone you can recommend or do you think that something / someone else might be a better fit"?

I really like this idea, I guess I never considered this as a possibility before. Nothing to lose by asking, though.