Geshtinnanna, I think webmaster was referring to sexual immoralities.
On My Way, you asked if the NAS or the NKJV has the correct rendering. The only way to answer your question is to research the two text types. However Mark wrote:
Mark 10:10-12
10 And in the house the disciples began questioning Him about this again. 11 And He said to them, "Whoever divorces his wife and marries another woman commits adultery against her; 12 and if she herself divorces her husband and marries another man, she is committing adultery."
NAS