"My guess is that Kerry got a settlement from his wife instead of the other way around. In other words, he took money from her and then had the marriage annulled after he found a new source of funds."
That makes sense, otherwise, based on what DJtex said, he would just go ahead and release the documents.
In the mid nineties, just before Kerry married Theresa, Kerry's wife took him back to court to request a change in the child care payments. He claimed that he couldn't pay because he didn't make enough money. My guess is that she wanted him to pay for college and he refused. So he married Theresa and had the kids declared illegitimate.