Gotta call bullchit on this one. Of course people can change who they are. That's like saying once a criminal always a criminal. Same thing for an addict.
Your W's actions are a CHOICE. She wasn't BORN poly. It's her choice to be so. It's not like it's the color of her skin. It's a learned behavior that can be changed like anything else. Think I'm wrong? Believe it or not, there were/are alot of poly couples on here where one partner just decided they didn't want to do it anymore. Simple as that. It's a choice.
And besides, if you didn't think your W is going to change, why are you here? Why do you think you have to change? Your assumption that her choice of being poly excuses her for treating you like $hit with OM. Not multiple men. ONE man. So right now that makes it a one to one problem like everyone elses.
Stop going by HER terms. If you can't stand to see your W banging other men and loving them, then stop. Kick her out of the house and stop being a doormat. If you continue to more of the same, you're going to keep getting the same.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.