I’m monogamous myself, but personally know two different polyamorous relationships. 1 is pretty damn good, and the other is rife with drama. Besides that, I tangentially know of others, and all of those are rough, though since I’m hearing of these from mutual friends and acquaintances, I could just be getting the juicy drama and none of the good parts. Could very well be that my info on those are bad
It does seem to mirror the general expectation, though, that most are unstable, and I wouldn’t call it surprising. Relationships are complicated, and anything that has more moving parts is going to be more complicated. I’m not trying to suggest here that monogamy is the way to go by any means–different people have different wants and needs, and some people are just good for polyamory. I just think that a working arrangement like this is tough to pull off
Besides, this gets asked a lot about polyamorous relationships, but there are so many fucked heteronormative relationships, and you never see the argument that monogamy is wrong, so yeah. Just whatever makes you happy