... Those who end up in court failed to be reasonable.
You must live in a very unusual place. I know of one father who just got his kids. Unfortunately it took their drug addicted mother dying from an apparent overdose in order to get the courts to give him the kids. Even though she had a record, her parents said she wasn't a good mother, and the kids wanted to live with him.
I never said that all fathers get raped. But it happens frequently enough that a young man (or not quite so young man) has to be very careful before he gets married. A pre-nup is all but required to be safe from activist judges
First rule of social policy, don't use extremely broken examples to make the rules. If the mother was drug addicted and disfunctional, I bet when they were together they had that in common. I don't know many drug users who don't share that with most of the people in their life. Clearly, there's more to the story, as always.
Here in Kalistan judges have been known to throw out pre-nups.