Local Fed's post is basically /thread. There's almost nothing more to add. My opinion is just... If she's asking you to open up the relationship, run for the hills. Either she wants to keep you as a security blanket, or she means well and hasn't thought what an open relationship means, or she's sexually unsatisfied, but in any case, it's an instant, no-return dealbreaker. Have some self respect. You can't compete with the volume of attention she's gonna get if she's just looking for casual dickdowns, and you're gonna come back home to her fucking someone else plenty of times. If you're a man, poly's just a fancy word for cuck, no matter how much you wanna whitewash it.
And if you were a pretty, attractive, young woman, you'd just go into sugar dating instead. Offers all the benefits you are realistically looking for without having to hang out with crazies. As Local Fed put very well, it is mostly about sex. Sometimes it's also about support and money, but it is mostly about sex. Somebody who can detach the exclusivity from a couple is just not good couple material, and if they want to fuck around, good on them, but trying to have multiple couples is just unfeasible nonsense. The men doom themselves to cuckery, and them being in a poly relationship will just kill any chance of having a good relationship with a decent woman they might have had in the first place. The women get constantly pump and dumped, comboing into a surprised Pikachu face when all these men only ever really wanted no strings attached sex from them, and maybe the thrill of cucking some omega male.
If you've been married twenty years, you have kids, and the spark is just gone, taking on lovers while remaining married for convenience reasons can be an okay solution, but actual polyamory... It's horseshit. It's doomed to fail. Even the couples who supposedly pull it off are only lying to themselves and would be better off facing the music and splitting up. The very premise of polyamory is "You know what, George, I love you and want to stay with you for whatever, possibly financial reasons, but I would also very much like to get gangbanged by Tyrone and his friends. And maybe take a crack at dating my boss while I'm at it." If you take that deal as a man, you're a self-hating retard. The very fact that your wife floated the idea should be enough for you to dump her then and there.
David Bowie did force this on his wife and got away with it, but I doubt the average man considering this is David Bowie.