I was 13 and my younger sister was 10. I strongly believe that it depends on the personalities of the children involved.
My parents were happy, no arguments, happy family life until my dad suddenly had a mid-life crisis, affair and left. Neither parent bad-mouthed the other after it happened although my mum had a nervous breakdown and I had bore the brunt of looking after her (a social worker used to visit once a week to check she hadn't killed herself as part of their 'suicide watch'!)
I have a strong, stubborn personality. Refused to 'talk about it' with friends and tried to be strong for everyone. I rebelled against it in that I tried to prove people wrong who said I wouldn't become anything as I came from a broken home so I got the best GCSE results in my school and went on to get degree, MA, great job, happily married. Underneath it all I am insecure, have found it difficult to say 'no' in relationships with men (I guess in case they leave me too) and don't like upsetting family (in case they leave).
My sister has a strong, stubborn personality and her response was to live up to the reputation of coming from a broken home. Drugs, many unsuitable men, dropped out of college, changes jobs and men frequently even she is now 30. She craves male attention and male approval (as a substitute for our dad).
We both had the same family life and upbringing and very similar personalities but reacted in totally different ways.