Oh, it sounds like you just want "play partners" without emotional involvement. That's not exactly a secondary. There is a website with a very popular page called a Secondary's Bill of Rights" here, if you want to read about a Secondary's point of view: http://www.xeromag.com/fvsecondary.html
I don't think anyone would really want to enter into any meaningful relationship being told they are not as important as someone else, even if it is a spouse -- unless it's just primarily a sexual relationship where no emotions are involved and the secondary is okay with that. As Mags said, usually having a primary and secondary in polyamory means there is love and emotional investment, but that the primary is the one who shares more of the heavy-duty responsibilities like finances, real estate, parenting, etc., and a secondary may often be secondary simply because of scheduling/availability, ie., not being able to spend as much time together. But secondaries are loved and respected and shouldn't be considered expendable. It isn't cool to unceremoniously dump a secondary.
I really think that you are looking more for recreational, casual sex partners rather than polyamorous [love] relationships.