First, you need to understand that you’re asking the wrong question.
Child custody is not a zero-sum game; otherwise stated, when parents divorce, or when unmarried parents separate, where you get the idea that the children must be in the custody of one parent or the other, but not in the joint custody of both?
Perhaps it has come from the idea you been taught most of your life that children of divorced or separated parents must spend the majority of their time in the custody of one parent. I’m 52 years old at the time I write this, and throughout my youth I was taught that very thing.
Not only were we taught the children should spend most of their time in the custody of just one parent, but we were taught that the parent that should be the “custodial” or primary custodial” parent was the mother. Almost always the mother. The mother, unless it could be proven that the mother was heinously unfit to have custody of the children. It was not uncommon to hear about perfectly good and decent fathers not being awarded custody or not being awarded joint physical custody of their children even when mom had a substance abuse problem or was physically and/or emotionally abusive.
The idea that children could be or should be cared for equally or as near to equally as possible by both parents was in the not so distant past unthinkable. The idea of children being cared for by their fathers was believed to be emotionally and psychologically damaging to children, especially very young children. The more research that is conducted on the subject, however, the more we learn that such thinking is wrong. I’ll be the first to admit that, especially in American culture, it seemed somewhat intuitive to believe that children might need or fare better in the care of their mothers instead of their fathers, but it turns out that’s false.
Unfortunately, the legal profession and the courts have been very slow to accept, let alone embrace, this fact. But things are changing in the legal profession and the courts, and at a comparatively rapid pace.
Now (I write this May 27, 2021), things are different, or I should say they are becoming different. As well they should be. Just as this country realized it made no sense to make the black man or woman sit at the back of the bus and that all citizens deserve fair and equal treatment under the law, it makes no sense to deny children of as much love and care and companionship of both of their loving, fit parents as possible.
To crib from C.S. Lewis a bit, asking which fit parent the children are better off with is like asking which blade of the scissors we’re better off with.
When children have to loving, caring parents who are physically and emotionally and financially capable of providing the minimally necessary levels of care their children require, there is no to deny children the benefits of being reared by both parents equally. Period.