We have 2 normal, well rounded teens who have not been traumatized by the fact that they have always known their parents were poly. At first we introduced our others as friends then the kids would just get used to seeing them there but as they got older we would tell them the truth, to them this was just normal so they were cool with it. We chose, when we started having kids, to never lie to our kids or hide anything from them but as with any "marriage" what goes on behind closed doors stays there (ie, we don't discuss our sex life with the children). I have always taught my kids to be who and what they are and to do and be that which will make them proud of themselves. I have also taught them never to let anyone else dictate how they feel about themselves or the things they do (though I do think staying within the confines of the law is good
) I have also tried to instill in them the wisdom to make choices wisely and with an open mind because closed minds are minds that have no way to reach beyond the mundane and there is so much more out there.