In the King James version. That is not the Bible Catholics use.
What are you talking about:
Matthew 5:32 from the Catholic Bible:
But I say to you, that whosoever shall put away his wife, excepting for the cause of fornication, maketh her to commit adultery: and he that shall marry her that is put away, committeth adultery.
Matthew 19:9
And I say to you, that whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and he that shall marry her that is put away, committeth adultery.
While Mark's Gospel does mention the exception for fornication in the Catholic version, Matthew clearly does. I think you might want to check your Catholic Bible again.