To be fair, your first reply could be read as a little insulting. Instead of
I am not interested in being a plaything for a couple.
you could have just said, "Thank you for your interest. However, I am not interested in dating a couple, as I prefer to date individuals (or one-on-one, or however you want to say it). Happy New Year to you as well." You chose to include what could be read as a snarky, condescending little judgement, and got called on it. He wasn't rude until you decided to educate (i.e. lecture) him, which wasn't necessary. You could have just said a polite "No thank you" and left it at that, since he wasn't asking for your opinion of what he was looking for.