I started this thread ("Can this marriage be saved?"):
http://www.dcurbanmom.com/jforum/posts/list/465130.page
All I can say is that you are not the only one in an "opposites once attracted and now they repel" sort of marriage. I am going to try counseling.
All I can say for childless or single people reading on is that you should be very careful not only who you marry, but also who you reproduce with. You can always divorce a husband, but you can't divorce your children. Once you share children with someone, they are part of your life for good.