Generally, I think that it is a good idea to establish boundaries. After all, this is a relationship which tends to be rather intimate, at least emotionally.

Was it just that he assumed you would date him? If so, he was just being an ignorant pig. Unfortunately, personality tests are not required to get into dance.

If you are married or in a serious relationship, obviously, your prospecive partner should know [politely and tactfully - I am a man and would appreciate that!]. If you are open to dating a prospective partner some time in the future, which may or may not be the guy that you are currently working with, I would suggest asking this prospective partner about his expectations for what will happen in your dance relationship. Alternatively, you can ask him what his girlfriend thinks about his dancing. See how he reacts so that you can guage how serious he is about his dancing. If he responds that there is no girlfriend, and likely asks about your boyfriend and you do not have one, you could always say that you recently split and won't be dating for a while, so you will focus on dancing. I am not a fan of lying as a matter of principle, but I do know how hard it can be to find a suitable partner.

I am currently looking for a partner, and I am amazed at how many ads for dance partners are actually thinly veiled personals. This is especially true for guys posting ads, which is why I did not place an ad, but am trying to network instead.

Best of luck to you!