Arrggghh!
My Dad will be fine, concerned, supportive and helpful.
My mum though, she will be straight up angry. She will refuse to believe that we're all ok (we're all, ex DP included, infinitely happier). She will get on my back about money and will try to guilt trip me about the DC being from a "broken home" 
.
I actually think it's partly projection. She and my dad should have divorced years ago and I think she is almost envious of people doing what she didn't.
Also, my sister and her DH split briefly last year after he cheated and I was astounded at my parents reaction. Lots of crying and obsessing and convincing my sister to take him back "for the kids".
I need to tell them but it's so hard knowing how my mother will react.
Eurgh. I'm 35 and I'm acting like 12 year old me when I broke something of my mother's and tried to hide it rather than tell her.