“Putting away” without a certificate of divorce is wrong. The woman who has been “put away” needs a certificate of divorce in order to marry someone else without committing adultery.
Discussion
That doesn't check out. Would the Disciples really have found it so onerous to provide a certificate that they'd find it not good to marry at all?
Matthew 19:10: "His disciples say unto him, If the case of the man be so with his wife, it is not good to marry."