I've watched a lot of unfair custody results, especially when a custodial parent decides to take the child and move far away from the area where the child has been raised. To me the solution to this particular problem is simple: when one parent, whether the primary custodian or not, decides they want/need/must move too far away for there to be at least regular weekend visitation with the other parent, then the "stationary" parent is granted primary custody, unless proven unfit. Period. No exceptions. This assures that the parent contemplating a move is not allowed to arbitrarily deprive the other fit parent of the right to be a real part of their child's life. It also assures more stability for the child, who will remain in a familiar environment (this may also increase the involvement with the child of parents, aunts, uncles, etc). Let's face it -- parents who decide on their own that its OK to separate their child from the other parent, unless the other parent is dangerous to the child, are making a selfish decision, and are not placing the welfare of the child 1st. Even if the move means a much higher standard of living, no amount of money can replace a good parent.

I agree completely.

But that leads to the obvious followup: if we're going to apply that policy to the physical locus of the child's upbringing, why not apply it to the child's human environment too? Absent a criminal conviction for abuse or felony, when one parent unilaterally decides to break up the marriage or partnership, the other parent is given primary custody if he or she wants it, unless proven unfit.

How can anyone claim with a straight face to protect the best interest of the child and then turn around and reward the person who breaks up the child's home?

I think that there is a distinction between filing for divorce and moving to another state.

You're presumption would basically create a situation where the spouses have an incentive to make life unlivable for each other so that the other one will be the one to actually file the divorce papers. I cannot see how this would be in any way healthy for the children involved.

Further you presume that divorce is always bad for the children involved (at least absent abuse by one parent). I don't think that this is the case. While it would be great for every child to be raised by two loving parents in a 1950's style sit-com family, that is not the case. When parents truly cannot live with each other, I strongly suspect that it is healthier for them to get divorced than for a child to grow up in a home full of hate and/or resentment.