I noticed something to the effect that as much as you enjoy seeing Ryl on a much more regular basis nowadays, you also wonder whether you'll be able to re-adapt to monogamous life after all those years of coping with polyamory. Seeing her home everyday? Alien. Forgotten. Perhaps uncomfortable, or you are thinking this unfamiliar feeling must be discomfort. After all, you taught yourself to be more alone and more independent and got used to it. Is this a type of damage that can be undone?
Intuitively, I find that the joy with which you speak of seeing her and being with her nowadays is a hopeful sign. Like SNeacail was getting at, some of the dysfunctional walls may take years to take down. If I may break protocol and paraphrase Ryl, she spoke of tackling those walls one brick at a time if that's what it took. But walls aren't invincible; like the trickle of water that erodes and breaks the stone, they can come down. What you can't do is change your natures if you're a monogamy-only type and a polyamory-only type respectively. Whether that's what your up against remains to be seen. As the old walls slowly diminish, your view of the long-term will broaden.
One important thing that's come of all this is that Ryl's seen first-hand that your misgivings of years past were not off-key. I at least think you can hope for her to listen to you more and take your concerns more seriously in the future.
I guess I can see how it could all end in divorce, but were I a betting man I think I'd put my money on you two growing old together. I think you both have the desire and determination that a lifelong marriage takes.
Love means never having to say, "Put down that meat cleaver!"