It'll settle. Just give it some more time.
Re: Polyamory.com and other poly venues ... it's probably useful to keep in mind that quite a few poly people consider polyamory to be more evolved, universally healthier, etc., than monogamy. So it's not too big of a surprise when some poly person says, "You shouldn't interfere with Ry's polyamory, you should let her be free." In some cases, that sort of thing might be true, so it seems hard to argue with. Who can argue with the ideal of freedom?
Luckily, not all poly people are of that perspective. Some of us willingly recognize that monogamy is okay too, and that it really depends on the individuals involved. Based on what I've read in your threads, monogamy is a hard-wired requisite for you, and as it turns out, polyamory doesn't work well for Ry either when there are kids as well as a spouse (and job) to tend to. In that case, it has to do with the allocation of time. Love may be an infinite resource, but time remains finite (particularly for us mortals).
Finally, there is the fact that even though polyamory (as well as monogamy) may have its general virtues, it's not going to work in a "cowgirl situation" where Si wants to lasso Ry out of the herd and separate her from you. You had a gut instinct about the "cowgirling" that was going on, but couldn't get universal support from poly folks because of the widespread idea that "polyamory is superior to monogamy, so it's the monogamist who must prove their innocence."
It's not fun to find out that a certain group or class of people can't always be trusted, especially when you need to rely on them for good advice. All I can suggest is, forgive the bad apples for the sake of the good apples. Doesn't mean you have to trust the bad apples; you've learned on your own steam who can be trusted and who can't. Just means free yourself from any ill will or bitterness that remains.
It saddens me that "the monogamous guy" has to do the thinking for "the polyamorous camp." But it demonstrates what I was saying: Polyamory and monogamy both have their bad points and good points, their advanced souls and their primitive souls. Neither "romantic orientation" is superior to the other, and one class is not obligated to take the other class at their word. It suffices to hear what people have to say, and then decide for yourself which advice is right for your situation. If something seems hinky, your instincts are probably trying to give you fair warning.
I think the quality of anyone's advice hangs on the quality of their listening. If they really hear you and come to understand the unique dynamics of your situation, then they're in a better position to give you appropriate advice. If someone bases their advice on some one-size-fits-all ideal, then they're probably not listening very well.
I know you have been stung by the polyamorous world, but try to let that sting fade into the past as your present and future are much brighter. Not in the least because you have earned some additional wisdom along the way.
With a spirit of fellowship,
Love means never having to say, "Put down that meat cleaver!"