Okay, let me see if I can help here.
First, I think that any advice I get here has to be internalized by me and I can then figure out what I want to do with it. That's my responsibility. So you should never feel that you need to preface your comments as a 'newbie.' All the advice I get here is appreciated and used as part of my process of dealing with this.
Next, the permanence topic. I do think it's a very safe bet that I will never be happy with my wife loving someone else. I know myself well enough to say this.
Next, the equity issue. I agree that when you add it all up, all parties in a relationship should feel like they got their fair shake. I am hoping that if I don't leave her, and we continue down this path, that we will settle into an equitable situation. If not, then it won't work. I fully expect ups and downs. And I also told her that I reserve the right to, at some point, begin practicing polyamory myself. I wouldn't do it with revenge as a motivation. I would do it to fulfill my own emotional needs.
I hope all that explanation helps. Thanks.