I'm the kind who likes both talking about things and hearing about things. However, when Seamus started seeing his girlfriend for instance, and shared things with me, it was crucial that she was fine with that.
Similarly, I wouldn't want to share details about a partner to another without getting the okay from them.
I think your partner is being unrealistic. Some people care about their privacy, and don't want every details shared behind their backs with someone who isn't part of the relationship. I agree that it will be hard to find someone who agrees to these terms, even though I don't like to hide anything, if someone's partner demanded to know everything I would probably be scarred off by them, as it would sound to me like they are controlling, and I want freedom over my own relationships.