Hi Passionate1. I am fairly new to the whole topic of Poly, but I think I understand how you feel to some degree. I just recently realized I am poly though I never knew what to call it. My wife and I are in very early discussions on this topic. She is working on her insecurities and has come a long way, but I don't know if she will ever get there. We've been married 18 years and I would never leave her, but I feel like I have room in my life to love more than one person. In fact I need to. And loving another will not take away from loving my wife.
For me the major obstacle is overcoming our religious upbringing and still having very religious friends.
I don't know if my reply helps you except to say that you are not the only one in your situation. The question is, how do you deal with one being poly and not the other........ When one is happy the other is not and so the circle goes on. I interested in discussing further if it helps you.