That’s a bit of my own stuff, but the main sources for that bit were D.A. Carson’s commentary on Matthew, and James R. Edwards’ commentaries on Mark and Luke, as well as these:
William F. Luck, Sr., Divorce and Re-Marriage: Recovering the Biblical View. Here is a link to Chapter 6, The Teachings of Jesus on Divorce
Craig Blomberg, Jesus and the Gospels: An Introduction and Survey.
If you’re looking for a general overview of the historical context, I recommend Blomberg. Good place to start.
Edit: Deleted the Evans book. Good book, but it wasn’t a source for this part.