Whether you are wired
monogamous or not is an individual thing. Like being gay or straight. You simply are or aren't.
monogamous is usually a social programming thing which makes people conform like denying your true sexual identity and pretending to be straight.
It's best that you find someone who fits into your life but keep an open mind towards others that don't have relationships the way you want to. Jealousy and insecurity are not the main reason mono wired people aren't poly LOL! It's merely a nature thing.
That would be like me saying selfishness and nymphomania is why people are poly. How insulting is that?
Good luck my friend and I hope you find your way