Hi nightdream,
I understand how you're feeling with this. Having read all the reply posts, it looks like there are lots of triggers for many of us in this subject.
I have read up a lot of stuff about estrangement. Most of it was aimed at reconciling, which didn't help me, but one person said, "Sometimes estrangement is necessary because the alternative is too destructive."
Those were wise words. I don't think that estrangement is ever a first choice, it's the very last choice, when there is nowhere else to go.
One thing I did, was to write regular, polite and newsy letters to my parents over a period of years, but I never was able to read their replies. I had to get someone else to look at them for me.
That's estrangement.
Good luck, Myzen