The underlying problem is irresponsibility, on the part of both participants. Unless, of course, he is getting screwed in more ways thn one, and her plan is to get pregnant in order to collect the check. He may be told that she has taken care of pregnancy protection when she has not.
Although the balance sheet doesn't work for productive people, in the low income spectrum, it works hand in hand with state and federal programs (WIC, low income housing, etc.) to add up to a modest living. The real victims of this are children who may grow up as a bargaining chip. Dad can do something about that, but it takes determination and effort.
Bottom line: Guys have a choice, and they are exercising it, in the bedroom as well as at the altar.
This removes one of the premier means of traditional control women have exerted over men.
This is one of the few areas where guy do have a choice...and control. I'm amazed at the number of posters who think that men "had it coming" when they got married/had sex, etc...then bitch because men don't choose to play anymore.