"There seems to be a popular misconception that joint physical custody means the children spend exactly one-half their time with each parent. Such an arrangement, of course, leaves the child with no time of his or her own to spend with friends. It also elevates parental rights over children's rights and virtually treats the child as the parents' possession. It fails to take into account that the maximum personal growth and development of a child occurs from both a loving and supportive relationship within the family and the development of personal relationships outside the family. Parents' demands for equal amounts of a child's time constitute a disservice to the child, usually creating stress and preventing the child from fully achieving his or her potential. In some cases the nature of the relationship between the parents may necessitate this kind of inflexibility. Usually it is temporary, and when the former spouses have adjusted to their new and limited relationship as parents of the same children, mathematical exactitude of time is no longer necessary. That has not occurred here.

Equal division of a child's time between the parents is not the hallmark of joint custody. After all, Civil Code section 4600, subdivision (b), provides 'Custody should be awarded ... according to the best interests of the child ....' Thus, the primary focus must be what is best for the child, not what is best for the parents. Although time is important to the parents, the determining factor as to whether joint physical custody is in the best (*1516) interest of the child is the nature of the parenting relationship between the parents."