I have to agree with the people who think her statement is part of a larger issue of hers, but I would like to see you follow up with a urologist. Sometimes surgeons and GI's have too narrow a point of view.
Joint therapy might help her discover what that larger issue really is. After almost 30 years of marriage, I do not believe that sex is the glue to a marriage or that a marriage is a failure if there is a break in the couple's sex life. Joint therapy can help clear the air. Rekindling the romance after a bad time can make both the marriage and sex twice as enjoyable as before.
Marriage can be tough. Sometimes it takes a lot of patience and forgiveness to get through the rough times. No matter what I hope things get better for you.