>>A divorce at the time Jesus said this, if valid, always included the right of remarriage. The divorce decree declared that the divorced party was free to remarry. This is how Jesus' original audience would have understood his words.
What you say sounds reasonable -- but remember what Jesus said -- Moses allowed it because of the hardness of their hearts. Jesus put an end to it! (Which is why he referenced Moses and then basically said it's ove!!)
He basically put end to the Mosaic practice of divorce and remarriage.
And later in this dialogue, Jesus provided the exception for divorce on the basis of the occurence of porneia within the marriage.
This is according to Matthew, the only one of the gospel writers who is likely to have witnessed the actual interchange with Jesus.
Both the Mark and the Luke account are, at best, second-hand.
The Matthew account is the most reliable, by virtue of the fact that only Matthew, of all the the gospel writers on the subject, would have actually witnessed this particular episode.
Note that the writer of the piece implicitly accuses Matthew of slanting his testimony, so that his gospel (testimony) would appear to be more consistent.
If one were to take such an approach to the whole of scripture, there would be little grounds for believing any of it.
As to the use of the Greek word 'porneia' in the exception clause stated by Jesus (per the testimony of Matthew ... do you actually accuse Matthew of placing words in Jesus' mouth ?), ... this actually widens the exception clause, rather than restricts it.
As the writer has clearly stated, adultery is but one form of 'porneia' (or sexual immorality), ... other forms would include pre-marital sex (thus covering Mary & Jospeh's situation), homesexuality, bestiality, etc.
There is, therefore, absolutely, no argument for excluding adultery from what is covered in Jesus' statement.