leelee I'm not saying you're not poly but maybe you are expecting too much from it. The part about wanting an actual relationship and not just sex isn't unreasonable but the part where finding a poly partner means you're going to automatically get x,y,z is.
People who are in open relationships are like any other group of people, some are lousy people, some aren't. You're probably not increasing your odds of finding someone who is looking for the exact type of relationship you are looking for and who will treat you well and respect you. In fact by looking for not just a guy who identifies as poly, but a guy who is already in a primary relationship you are sort of painting yourself with unicorn/third sex partner hunter bait. Obviously that isn't what you are looking for but it probably sounds close enough for you to be attracting them. I guess what I'm trying to say is, listen to NYC. Maybe let go a bit of the poly term and just stick to that description of what you are looking for and what you are looking to give. If someone approaches you with some other idea its easier to say thats not what I'm looking for and not be confused by what you think poly should be not matching what others thing poly should be.