I've been following both your blog and your wife's blog here, so I know that at least the two people most closely involved with the situation are in agreement about what's been going down. I've stated it on Ry's blog so I'll say it here, I think you tried to repress your reservations for a long time until it just exploded. So, if I perceive any bitterness in your posts, that's what I ascribe it to.
I think forgiveness and trust are two different things. You can forgive someone (not wish them ill will) without allowing them inside your boundaries again, or steering yourself into their whirlpool. Si needs to learn from the experiences of the past decade, and proceed with her own life. You and Ry have been doing much better together since transitioning to a monogamous relationship. I see no reason to fight that.
I actually think your latest posts are a fair sight less bitter than any earlier posts I can think of, so I think you are getting over it, in your own time and in your own way.
I think the best thing you can do is focus on the good things you have in your marriage right now. The bad things seem to be fading into the past (like a bad dream). And perhaps it is some consolation to know that you can trust your own instincts.
Thanks for keeping us posted on how things are going from your end of the spectrum.
Love means never having to say, "Put down that meat cleaver!"