Updated with a brief explanantion
By Timothy Sparks
(I have modified Roy Deaver’s diagram in his Harding Lecture, “Marriage, Divorce, and Remarriage,” April 19, 1977. While I give a brief explanation below, for a technical or simplified answer, please send an email.)
Click link for magnified view: Greek Diagram of Matthew 19:9
A brief explanation:
The exclusion clause μὴ ἐπὶ πορνείᾳ (“not over fornication”) modifies only the verb ἀπολύσῃ (“may have dismissed”). It does not modify μοιχᾶται (“commits adultery”). In fact, μὴ ἐπὶ πορνείᾳ (“not over fornication”) does not affect anything else in the sentence. Therefore, μὴ ἐπὶ πορνείᾳ does not change the meaning of μοιχᾶται.
For the diagram of my English translation of Mt. 19:9, click here: https://timothysparks.com/2015/12/01/matthew-199-english-parallel-to-greek-diagram.