But if you look at the thread "Is poly worth it" it's predominantly positive. I look around at all my old mono friends and they may not have the emotional roller coaster rides that poly relationships often include but they are mostly a lot less healthy, honest and dynamic than my relationship and I'm sure yours. Many of them are "affairs in waiting".
I have also had kids and a long mono relationship peppered with affairs, so maybe that has helped me get where I am. I don't have any illusions about a mono relationship necessarily being any better than a poly one just because it's mono. Any relationship is only as good as the people in it.