We have one rule. It is a rule that applied to mono and poly relationships equally.
If Safe Sex does not occur, and I find out about it, unspeakable consequences will arise.
Oh, Shannon has expressed a preference I don't sleep with any of their relatives (have to adopt a look but don't touch attitude here, a particular cousin is VERY nice to look at). It is not a "rule", but it is something I shall respect.
A long list of rules would just be confusing. And sometimes rules are harder to follow for other parties. I am better at telling Shannon where I am and what time I am due home. I am naturally more organized (and have a car so don't rely on public transport, and always have credit on my phone!). Having a rule stating that I must be told where/when/who would just result in grief.
If rules are being broken frequently, more conversation is needed. And a consideration of compromises for both sides.