A conversation I semi-regularly have with people I don't know that well:
Person: "How long have you and your girlfriend been together Nick?"
Me: "About 6 years."
"Ooh. Any plans to get married?"
"Ha. No, we're not planning on it."
"I bet she wants to though."
"Oh, of course you think she doesn't, but she really does. You'd better hurry up, she's not going to wait around forever you know."
"No, she really doesn't want to get married right now. Neither of us do."
"Of course she does! Trust me."
So you think that:
(A) You know my girlfriend, who I've been with for six years, better than I do - even though you've never met her - because;
(B) as a man, I am too dumb to understand that;
(C) all women want to get married as soon as possible, but just won't admit it.
And (A) means that you have to inform me of this, otherwise she will leave me because of (C) and I won't understand why, due to (B).
Well it's a good job you know your stereotypes better than I know my girlfriend.