why is there a wife support in a divorce? when there are no children involved?

Alimony or maintenance is ordered where one person foregoes education or employment opportunities in the belief that they are part of a couple that will continue "until death do us part," and that there is value to working for the benefit of the couple at pursuits that advance the couple, not that person's individual future.  So, if one person stays at home, does the laundry, cooks the food, cleans the house, buys the food and clothes, arranges for the repairs to the house and vehicles, etc., and the other party goes out and works as hard as possible, etc., when they split up, the person who was working hard for a pay check, still has a job and decent prospects.  The other person needs to start over.  Keep in mind the eternal truth:  why does a divorce cost so much?  Because it's worth it.