I don't share details, nor do I ask - I have told hubby about some fantasies I'd like to pursue, things that really don't interest him. It's all theoretical at this point, but while he knows some of the broad strokes I won't be giving him the minute details. I don't tell my friends details either, so this is pretty consistent for me.
As for him, I don't ask about the details of things with his girlfriend - I might ask how the day went or nonsexual stuff, but I think they deserve some privacy so I don't pry.
It might change if we were both involved with the same person (or a couple) but I kinda doubt it.
And like many others, I don't want anyone broadcasting details of my intimate life without permission. It seems disrespectful.