There's no such rule. Something is decidedly wrong. Maybe your king was just being chivalrous. LOL.
king taking queen
It'd help to show the game first. There's no possible way, other than you overlooking a protector of the queen.
Edit: Well, I just viewed the only game in your profile, so assuming that is the game you're talking about, the queen was actually guarded by the bishop.
I just played a game and the opponent placed his queen next to my king twice and I could not take her.. his queen was completely unguarded.. I have never seen that rule before.. what's up with that?