To not keep you guessing evan: Because of the uniqueness of you and us all the poly-hood out there, I guess. Not that I want to convince you of the strangeness of such an idea (I read about some discussion going on in another thread already), but you won't find that many people on here who share your point of view in this regard.
Have to say that your life story is quite ... notable could be the right word *scratches head*. You have got your way of finding some extreme characters and persons for sure as it seems.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.