Arguably, the ideally fair and just outcome in such cases is a "shared parenting arrangement," where the child (or children) is under the care of each parent approximately 50% of the time and, of course, each parent has his or her child (or children) approximately 50% of the time. This is supported by concerns about children's rights, parents' rights, children's best interest, parents' best interests, and more.
Although becoming more common, "shared parenting" is not the norm, for a variety of complex reasons. The common practice is that child(ren) is with one parent most of the time and 'visit' with the other parent, every other weekend and one night a week.
Shared parenting should be the norm, however, and changes can be made in the the legal and court system to make that happen.
The relevant laws, regulations and procedures are mostly state specific. I am working with concerned individuals in Georgia to (1) make shared parenting a more readily available option (since the legal system is built around the assumption that there will be a "primary custodial parent" and a "non-custodial parent," and shared parenting doesn't fit that mold) and (2) create a shared parenting presumption, so that the legal burden is on those who argue that the initial position of equality and fairness is inappropriate for this particular case (in contrast to the current informal presumption, which requires arguing for equality and fairness). (I have noticed that many attorneys who opposed shared parenting presumptions misrepresent them as shared parenting mandates or requirements, which nobody argues for).
In addition to the legal and philosophical concerns about justice and fairness, there are also important concerns about gender norms, stereotypes and prejudices ('women and mothers are like this... men and fathers are like that...'), as well as social scientific questions about the psychological and emotional consequences of different custody arrangements. These issues also raise questions about the legal industry itself and whether there are alternative, less costly -- financially and emotionally -- ways for parents and children to achieve justice and fairness.
Here are a few recommended sources on these topics:
- Edward Kruk, "Sixteen Arguments in Support of Co-Parenting: What the Latest Research is Saying about the Best Interests of Children," and The Equal Parent Presumption: Social Justice in the Legal Determination of Parenting After Divorce (Mcgill Queens University Press, 2013)
- Don Hubin, "Parental Rights and Due Process," The Journal of Law and Family Studies 2(1999) 123-150.
- Linda Nielson, Wake Forest University, NC
- National Parents Organization
- Guideline Economics, Dr. Mark Rogers, a Georgia economist who specializes in child support economics
- My Advocate Center, Atlanta, GA
- Georgia Shared Parenting.org