In my case that means that I might tell DH. But in my friendship group that is the norm. And I think it would be unusual for someone I didn't know very well to come to me with such a classified/ top secret thing - certainly it tends to be more that you speak to close friends about more personal things. And in my case my friendship group all works the same in that regard.
Also, on the flip side, if I told a close friend something personal - even not knowing whether she would tell her partner - I would do so trusting her with that information. If she then told her partner (which I would probably never find out), I would trust that she had done so knowing that she could trust him with such personal information and that it would go no further. It wouldn't occur to me to stipulate who could/ couldn't be told something (about me, I mean). But I would only tell people who I trusted would make the right decisions in that regard, and if that meant telling someone else then I would have faith in my friend about why she told and who she told.
But, as I said before, it's never been an issue as I already know that my close friends would probably tell their husbands anything, and that's fine with me.
I probably didn't explain that very well!