Kimmerz - my xh still yanks on the chain occasionally, after nearly 7 years. Oddly enough nowadays he backs off if I act normal, if that makes sense. But that part took a long time.
For example I got birthday greetings this year, after none for several years, and my initial response was to ask him why he was doing this. All this produced was endless waffle about a shared past [which, he being a mean MLCer rapidly degenerated into it all being my problem]. So I let it lie, and then suggested a few months later that we meet up when we were both in the same city, and have a talk. That produced a panicky response and then a longgggg silence. They keep making sure we are still there, but the moment I say the equivalent of 'Still here, do you want to meet up' he heads for the hills. I also think the fact I can say that to him indicates that i have largely healed, and moved on - not saying they take this in at a conscious level but the way we respond to them conveys subtle messages that they no longer have the power over us, emotionally, that they had. And what is the point of 'punishing' someone who doesn't feel punished?
As for understanding them which is hard, I shifted the focus to understanding myself, and why I chose someone who had serious emotional issues [despite being a lovely husband for a very long time and a great father]. I found the book by Susan Andersen 'The Jounrey from Abandonment to Healing' one of the most helpful ones of all the many I read, partly because it had exercises to do, which worked, at least for me.