Hmmm. Poly & bi... Why does this seem so familiar?
Hey, wait a minute, I'm poly and bi -- and old enough to be your father!
Dude! You gotta somehow lower the drama factor. Here's an idea to consider, tell your love interests this: "I'm poly and bi. I love you, but if you can't live with who I am, then it's not gonna be working out. I'll hate to lose you, but I must be true to my own nature."
Something like that. ??!!??
And then drop the drama, man. Be happy. Be yourself and be happy.