I've heard a lot of people bash Rush, but I think they had it right when they said "If you choose not to decide, you still have made a choice." You may not have chosen between Wolf or Turtle, but you have chosen to keep everyone kind of strung along presumably until one (or both) of the men hit their breaking point.
My advice? Really try to explain to both of them where you're coming from. You say you wouldn't call yourself poly because it's time consuming. I think you are choosing not to follow your inner-poly because it's hard (which I totally get, but you probably won't feel fulfilled in your life if you just dismiss it entirely without considering what could be). Explain to them that you do love both of them and that you really want to be with them, but if they can't accept you for who you are then it isn't going to work. I know it sounds harsh, but if you dump one of them and end up married with kids with the other you will always have the 'what ifs' in your mind. What if they had come to accept you as poly? What if you had ended up with the other one? What if...? See if they are open to reading about vees and mono people who are involved with poly people. Maybe if they can see that it has worked for other people they will be willing to try it. The worst they can say is no.