Depending upon the arrangements, physical custody may be sole or joint, but primary physical custody.
Physical custody can be a particularly contentious issue; when a child lives with one parent, he or she obviously is not with the other. And no judge is a King Solomon who can cut the child in half to satisfy both parents.
In both physical and legal custody, judges are guided by the gold standard: the children before the divorce, a child’s preference (in some jurisdictions) -- all are considered in determining the custody arrangements that are in his or her best interest.
In many, if not most jurisdictions, courts are guided by the maternal preference. Put in a simple way, this means that, all other things being equal, a mother will get physical custody of small children. In general, courts seek to minimize the disruption to he child. In practice, this means that the child very often will end up with the mother in the family home (and the father, who once lived there, will now become an occasional visitor).
See also Sole Custody; Joint Legal Custody.