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well, sometimes some more mature couples can actually work out suitable arrangements without the legal system being needed to bust into their private lives.
Let me tell you as a once divorced man with legal custody issues brought on by a mean-spirited ex... having the law involved can be both a blessing and a curse, so I don't blame anyone who can avoid the law from stepping in from doing so.
When two mature people can agree and stick to their agreements... to me that is far better a situation for all concerned, especially the children.
Wouldn't you want to teach your children to learn to be mature problem solvers instead of vindictive fighters?
The law can make things nasty and a mess, and while know sometimes (unfortunately) it can be a necessary evil to have the law step in... but at the end of the day, and after much personal experience with this very issue I think it best to avoid including getting the law involved into your lives when and if at all possible.
For me, I'm so glad those days are long over.
I now can live in peace, with no ex to worry about anymore, and my relationship with my son is normal and not stressed by having the legal system involved any more... a very good thing to avoid the law, again, if possible.