I'm not sure I understand what you are getting at:  How does a dispute between two Talmudic Houses on when one may divorce his wife affect Jesus' apparent blanket condemnation of the practice (in Mark) or allowing for it only in the case of infidelity (in Matthew, which actually makes no sense since the offending spouse would be dead by stoning, anyway)?  Presented with a false dichotomy, Jesus points in another direction.