Where did you get the info about Casey being raised by a first husband? I read a while back that it was proved that Cindy has only been married once and only recently did her husband file for divorce.
However, your post led me to search further, not so easy with all the stuff you find under her name, and finally found on snopes.com that this story has become common and after they researched it they found it's an urban myth.
Here is the link:
http://www.snopes.com/politics/war/sheehan.asp