Not quite in answer to the OP but still related - I have an Aunt & uncle who separated / divorced when their kids were still young (school age) and it was almost a year before any of their teachers knew what had happened.
The reason being, they had handled it so well, there was zero drama, no stress, no fuss. The kids stayed with whoever they felt like staying with that night, and each parent accomodated what the kids wanted & needed.
I don't know all the ins & outs of how it went (I was quite young) but I still remember it as a brilliant example of how it can be ok - unfortunately as adults we often get so caught up in our own emotional drama it's rarely just about what the kids need (and I am guilty of that myself).
But to me, it illustrates what Kelly said - it's usually what goes on around the separation or divorce that causes problems.