Maybe because we're taught that men don't like to talk about emotions as much as women? We're told that men deal in the concrete, while women are more emotional, which may or may not be true. I've met men that talk about their emotions and also women who avoid discussions like that as though it's the plague.

Now that you've noticed, the behavior, maybe if you feel the need, say something like "I hope you don't mind me talking about x", and then don't say anything more apologetic.

You might try it and see whether the suggestion is of any value to you. Take care