People around here usually have a strong opinion about rules versus not rules. Either is ok. I guess you could say i have a "N" or "z" which is two people who are married who each have another partner (except my other partner also has other relationships which i do not always know about nor do i need to know). We play by the "not rules" system. This is working really well. Actually i don't use "poly" i use "open" because i like it better.
The problem is not the rules themselves, it's that one of you wants lots of rules and the other doesn't. What if you told him you decided "no" to non-monogamy? Then he gets to have his "no rules". No poly, no rules needed, right? Everybody wins. You tell him i said so. He's a big boy, he can handle it with his big-boy pants on!