The practical reason, is well, because even though many woman work today, historically, men have been the primary breadwinners of the family. So the women raise the children, men earn money.
When it comes times for divorce, the man's "contribution" is easy to see. Its the money. The woman's contribution isn't easy; it is the home-life, raising the children, etc. So the court would be unfair to say, "well, the man gets to keep all that he earned" unless they also give everything "else" to the woman (other than custody, a lot of that is intangible and has already been "spent"). Could you imagine the uproar if a court decided that a free man could never be in the same room with his kids, because his ex-wife was the one who raised them? Can you imagine how poorly that would be enforced?
That is why the courts rule the way. The idea is, that as husband and wife, the two of you built a life together. Just like the children aren't just the "mother's" since she raised them, the financial wealth and property isn't just the man's since his labor obtained them.
Obviously, there are times when the court deems financial restitution that is way too much, or even not enough, but that is the basic philosophy behind it.
There was a great example of this a few years back. Some millionaire sports owner, married for 20+ years, got divorced. His wife got half the team, and many cried foul. But this was the reasoning the court gave, especially since the man made his millions while married.
Plan for eliminating the national debt in 10-20 years:
Specific cuts; defense spending: http://rolexian.wordpress.com/2011/01/03/more-detailed-look-a