I have no intention of using any kind of “common” argument. I don’t have to. First, the two new testament quotes you lift are obviously both referencing the same incident. So it’s not like you are taking two different times that Jesus supposedly talked about sexual immorality.

Second, the translations For those verses come from Greek. They are not translations from their original Aramaic which Jesus spoke. So we don’t know if he actually even referenced it, and two we know that the words being used or based on the translators view of whatever their original Greek word meant. Bottom line, we do not have any clear indicative verses on the topic out of the mouth of Jesus. Which is why Theologians who have decades worth of knowledge and experience cannot all agree on this.

As far as any reference back to Old Testament law, how many of those laws that were considered sin during that day are no longer considered sins today? From the kind of food you can eat to that kind of clothes you can wear.

One thing we can feel confident about is how Jesus taught we should treat other people. And from my experience, the people who get all riled up with how people live their private lives are a lot less interested in actually treating people with the love that Jesus commanded.