ComingUndone, when I read what he says, "You don't want to be married anymore because I won't have sex with you?" He may be testing you to see if you will stay in the marriage. He wants to know that you love him and will not abandon him again.
Have you tried a marriage seminar? You both need to learn how to love each other again. Here is a link to retrovaille: http://www.retrouvaille.org/