When my quad started out, we had rules. I'm sure every new Polyamorous relationship does. Or maybe not.
But after awhile aren't the rules annoyingly restrictive? Making individual relationships seem less than authentic? Like you two can't really be yourselves without upsetting their significant other?
I like Mono's idea of thinking of some rules as criteria instead-- it's neat, Mon, hadn't occurred to me... What I use when I'm thinking about poly stuff is actually a pair of concepts: rights and responsibilities. For example, I have the right to be reasonably confident that I will not get an STD from my playmates or partners, which means that they have the responsibility to practice safer sex-- and because they have the same right, I also have that responsibility. (Rights and responsibilities tend to be opposite sides of the same coin, in my experience.)
It is true that many new to poly want firm, potentially restrictive rules as they dip their toes in. It's also true that members of long-standing relationships (mono or poly) often have very firm rights and responsibilities.
In my constellation of relationships, if a rule is bothering me, I try to think about what right is being protected (and whose it is), and how that fits in with the responsibilities that seem problematic to me. That framework tends to put me in a more mature place for talking about the situation.
@Marco: If you feel like you can't be yourself, it's definitely re-evaluation time. I'd say you have the right to be yourself, and everyone involved with you (yourself included) has the responsibility to make that feasible. If I were in your shoes, I'd talk with everyone in the quad about how they're feeling when pet names are said-- Maybe it's just one specific one that's setting of hackles, or that everyone goes by the same name. I know I'm in a really permissive relationship with one of my primaries, and I still feel edgy and defensive every time he uses my pet name to address ANYONE else, even the cats!
In any case, good luck! Thanks for sharing.