There's an old saying I am sure you're familiar with: The definition of crazy is doing the same thing over and over and expecting different results. We're all guilty of this sometimes. The trick is to recognize it, and change your pattern. Again, you can't change your potential GF's actions. It sucks that she didn't react as you'd hoped or expected (because that always sucks), but it is what you have to work with. So, instead of the same reminders and suggestions for her behaviors, again, focus on
your expectations, boundaries, and actions. You do not have to participate. Sometimes, that stinks, because you like the person and want things to work; but, they don't always work, and you can't force other people to behave in a way that would make them work for you. You can control what you do, and how you react.
State your needs, set your boundaries and what you'll do if those boundaries can't be met in a relationship, and follow through.
As far as eating crow, I don't see why that would be necessary. The commenters here were genuinely trying to be helpful, and asked for some help in return. One account with multiple people posting is confusing as all get out, is against community guidelines/recommendations, and also leaves the impression of couple vs. outsider (even if that wasn't intentional).
The article I suggested your read wasn't supposed to be a negative commentary on your current relationship. You asked for advice on triads and how things worked, and it's got some fantastic examples of dynamics (that are, frankly, useful for many relationship configurations). It also should have helped explain why people tend to take a cautionary stance about triads where a couple insists on dating as a unit, and your posting as a unit compounded those feelings. And, whether you see it or not, there was definitely some resonance with that article in your posts. For example, assuming a "play as a unit or no go" stance in sex and dating. It was what you and your wife had decided ahead of time that put your potential GF into a smaller box, because her options were "yes or no," with no ability to negotiate for what she needed without the stated outcome of losing the relationship. With every decision the two of you make for how her relationship with each, and both, of you must look, the box gets smaller. It's a very difficult thing for someone coming into the relationship to deal with, because negotiating against a united front is often frightening and difficult, and it's easy to get trapped into the "the couple comes first" attitude, as well. If you didn't get from the article that at least some of those things were happening, at least according to what you posted here, then I can't think of a clearer way to show you.
No one posted with malicious intent, and I believe all of us posted honestly and with integrity. Some of the posts were harsher than others, and some posters definitely disagree with various things said or done; but, that is part of posting on the boards: a variety of outlooks, options, and perspectives. We don't all like what we are told all the time, but sometimes it's those posts that help the most if we really take a look at what they're saying (they certainly have me!).
I've proposed some times when I'd like to be in her neighborhood for a group bicycle ride and they could have some girl time while I'm out with the hopes of spending some time too. I/we are fine with being friends and taking things slow and continuing the organic development but gf must be uncomfortable with something. She has made clear that when she's uncomfortable she backs away but, complete disconnect was not expected. We've gone out of our way to be available for her and to gently remind her that we are still here. And yet here we are.
My greatest frustration now in many ways is the way that K and I have been treated here and I hope there is some crow being eaten. I feel it is clear that we are not the evil UHs that we've been made out to be and that we wouldn't be so torn up and distracted if we didn't have genuine compassionate feelings for this woman.
In will recognize a possibility of white knight syndrome but, I feel I'm looking up at Rapunzel and my armoir is far more tarnished than white.