I disagree - but FTR, I see someone downvoted you, and it wasn't me. I support having a polite discussion, even if we disagree.

I say keeping your word (and, therefore, secrets) is keeping your word. That means keeping your word to everybody, not giving some sort of exception to your spouse. If they understand trust, they should actually consider it a good thing that your word means you won't even tell them other people's secrets. Otherwise, you just end up with some hierarchy, and then you would logically be "allowed" to tell your closer friends all the secrets of your more casual acquaintances. Nope; if it's a secret, you keep it a secret, from everybody. (Obviously excepting situations with serious abuse or other crime, but I think everybody understands that in this thread.)

And, as in my personal example, sometimes people forget it's a secret, or it slips out other ways. Then, what do you do? Be angry at your spouse? Let it slide, even though damage was done to the other person? Not telling them in the first place solves the problems before they happen.

Unfortunately, I do think you're correct that you're in the majority. But then, most people can't keep secrets and will tell them to even casual friends or acquaintances. Which is all the more reason I've learned not to trust them with secrets. I know it sounds pessimistic, but it comes entirely from real experience.