What do you do when your parents are getting divorced?

And I don't mean this for the kids. I mean for us, as parents ourselves - what do we do when our parents decide to split up?

My own mom recently divorced her husband (my step-father) after almost 20 years of marriage. There was a big age difference, and a big difference of opinion on aging. She worked, he had been retired for 15 years already. Her job was moving five miles down the road, he complained it cost too much in gas. He criticized everything she did, and she finally had enough. There were other things too, that I won't get into. When she announced she was filing for divorce, I said "Good for you!". Her friends said the same thing. Her co-workers even said the same thing.

Honestly I never liked him in the first place. They married when I was eight - I'm now 28 - and this is the same man that single-mouthedly caused my eating disorder that I still can't shake 16 years later, caused me to move out at 15, and numerous other things. And of course, my mom is aware that I didn't like him. I found it very hard to conceal my complete elation at the news that they were splitting up.

So how do you be supportive of your adult parents divorcing, especially when you're not impartial? I've always kept it friendly with my step-father, despite my actual feelings for him, out of consideration for my mother - and I'm actually kind of hurt that I haven't heard a word from him since he moved out of my mother's house almost three months ago. At least mom is taking it well - she's got a real "I'm just fine on my own and I will survive" spirit (and a few shopping sprees probably didn't hurt) but I just can't find the right words to say.

Anyone been there done that? Any words of encouragement for me or her?