Amy, that's the key to verbal apologies—you have to know the other person means it, the way you did with your ex. And the other key, as you point out, is to never force or demand an apology. The way you've come to deal with "the other party to the affair" sounds very wise and healthy. Isn't it amazing how much we can learn when we go through something painful and difficult? 

GettingThere, I can completely relate to this: "I can be sorry, but can’t overcome the other emotions right away to express it." It's not that I don't feel sincerely sorry in these situations—it's just that expressing it is difficult. I also like your thought that the words "I'm sorry" open the door to action and healing. It's like a two-stage process, not an either-or thing. 

Marie, your sense about the actions making the words complete reminds me of the interactions I often have with one of my daughters. She does say "I'm sorry," but it tends to be in a rather snotty way, which always makes me say "Don't say you're sorry, act like you're sorry." What you say about the struggle being a good sign is right on. I'd rather know that she's feeling torn and confused than hear her apologize in a disingenuous way. (Btw, thanks for your kind words about my family and this post!)