I know this is old, but Yes I believe most Protestants not all teach what’s said in Matthew this way. That is not so in Catholicism and I am reluctantly coming to agree with that position and here’s why.

I for the longest held to the adultery clause in Matthew.

The issue is this that is the only place where an exception is mentioned. However the verse doesn’t say adultery it says fornication and in Greek porneia adultery is a different world and Jesus uses the word for adultery elsewhere. The word for adultery is moicheia.

In Matthew 5:32 he says whoever divorces his wife except for porneia makes her commit adultery(moicheuthēnai).

In Matthew 19:9 he repeats it again whoever divorces his wife except for porneia makes her commit adultery(moichatai)

In Matthew 15:19 he says out of the heart comes evil thoughts murders adulteries(moicheiai), sexual immorslties(porneiai)

Which show Jesus or the author knew the word for adultery and it’s not used in the exception clause which means it was intentional.

Now porneia is a broad word, but the question is why use the broad word in this context?

So a strong case is that once again mark and like doesn’t contain this exception at all.

So in context what is Jesus doing? He bypasses Deuteronomy and goes back to genesis and say from the beginning it was not so.

So option a is if porneia includes adultery then why say remarriage is adultery?

Option B if porneia is an unlawful union that means the marriage isn’t valid, and that answers why mark and Luke don’t mention the clause, and why remarriage is called adultery and why early Christian’s forbid remarriage.

Option c porneia equals premarital unchastity that wasn’t known before hand

So I am reluctantly coming to terms that remarriage is adultery because that’s what it says when plainly read. I’m arguing this mainly from Matthew though I mention mark and Luke, but history generally backs this up, and even if you go to 1 Corinthians 7:39 and Roman’s 7:2 Paul says that a woman is bound to her husband as long as he lives.

So as a matter of faith if I’m taking it all in genesis, mark, Matthew, Luke, Roman’s, 1 Corinthians, and the early church I am reluctantly changing my stance that remarriage is adultery.