You do realize that the woman you´re actually speaking of as regards to Jesus is none other than Mary Magdelene don´t you?.What we have available to us today, the known word of God in the holy scriptures,was made available to us by way of God's holy spirit.Books that are out there like the Gospel of Thomas for example are fraud books that do not contain the truth.That book in particular speaks of Jesus as a brat child that killed people.We have to be careful not to assume that everything out there, supposedly written by apostles, is true or God's inspired word.
Also,nice stories that sound great, like the one in John 8:1-12,sound awesome.It sounds like something Jesus would have said and done.The fact of the matter is that it was not included in the first copies of the holy writings found by archeologist, that we, use today for research.It was included much later.It could have happened,or maybe it did not.It was not John who wrote it.The books of John were the last of the holy scriptures to be written,c. 98 C.E.
By the time the bible was being put together in the 4th century,many other writings began to pop up.It was 200 years after the last of Jesus true disciples died.John died in Ephesus in about 100 C.E. His writings were complete when he died.That story in John 8 was not part of it.Someone included it much later.
And if sexual immorality weren´t considered a sin,he wouldn´t have told her to go and sin no more.
Later on Jesus himself said that all sins will be forgiven men/women if they truly repented of them.
Except one,be it in this world or the next,blasphemy of the Holy Spirit.
Now if our earthly bodies were considered temples of the Holy Spirit,or God if you will,whoa those of us who defile them to
satisfy our humanly lusts.
If you´re asking whether or not adultery etc, is admissable,then no it isn´t,in any form,as Jesus said,even looking at a woman lustfully is like your already
having committed adultery with her in your heart.
Hard as that may be to for us to digest.
One doesn´t have to think twice about how God feels about the matter.
God does not change to appease men,or better said,think as men think.
His thoughts are far above those of men.
In anything,listen to your conscience,as it will convict/convince you if you´re actually doing the wrong or right thing.