Why do men care?

I went out with some friends of mine from Forum Friday night and we talked about our relationships, which is what women do. We got started on it mainly because we were discussing the circumstances surrounding why one of our group got divorced. Anyway, that led to all of us mentioning difficult times we've had in our own relationships. I happened to mention this to my husband the following morning and he immediately got this closed up sort of look on his face, letting me know he wasn't pleased. He said he wasn't mad, but that men just don't like having their relationships discussed. I don't know if this is true, but if it is, why is that the case? Why would men care that women discuss their relationships? I wouldn't care if my husband talked to his friends about it. I mean, if we don't talk to our friends about it, who are we going to talk to about it? It has been my experience that most men would rather have their fingernails ripped out with pliers than be forced to talk about the state of the union with their significant others. This isn't something that's really bothering me or anything, I just think it's a weird thing for a person to get their panties in a bunch about.