Partner policies - I've heard of a couple who explicitly tell all of their other relationships something along the lines of "if you tell me anything, you're also telling it to my primary partner".

I'm quite squicked by that, actually, and I know it caused them some problems with some of their other partners.

Yes, I agree with you in terms of "if I'm bothered by something, I'd like to have access to my partner(s) to help me talk it through", but that's a preference, not a requirement.